Python之路【第二篇】：Python基础（一）
入门知识拾遗
一、作用域
对于变量的作用域，执行声明并在内存中存在，该变量就可以在下面的代码中使用。
if 1==1: name = 'JasonWang' print name
下面的结论对吗？
外层变量，可以被内层变量使用内层变量，无法被外层变量使用
二、三元运算
result = 值1 if 条件 else 值2
#三目运算符
name = 'aa' if 1 == 2 else 'SB'
print(name)
SB
如果条件为真：result = 值1
如果条件为假：result = 值2
三、进制
- 二进制，01
- 八进制，01234567
- 十进制，0123456789
- 十六进制，0123456789ABCDEF
Python基础
对于Python，一切事物都是对象，对象基于类创建
所以，以下这些值都是对象： "wupeiqi"、38、['北京', '上海', '深圳']，并且是根据不同的类生成的对象。
一、整数
如： 18、73、84
每一个整数都具备如下功能：
lass int(object): """ int(x=0) -> int or long int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments are given. If x is floating point, the conversion truncates towards zero. If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or Unicode object representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int('0b100', base=0) 4 """ def bit_length(self): """ 返回表示该数字的时占用的最少位数 """ """ int.bit_length() -> int Number of bits necessary to represent self in binary. >>> bin(37) '0b100101' >>> (37).bit_length() 6 """ return 0 def conjugate(self, *args, **kwargs): # real signature unknown """ 返回该复数的共轭复数 """ """ Returns self, the complex conjugate of any int. """ pass def __abs__(self): """ 返回绝对值 """ """ x.__abs__() <==> abs(x) """ pass def __add__(self, y): """ x.__add__(y) <==> x+y """ pass def __and__(self, y): """ x.__and__(y) <==> x&y """ pass def __cmp__(self, y): """ 比较两个数大小 """ """ x.__cmp__(y) <==> cmp(x,y) """ pass def __coerce__(self, y): """ 强制生成一个元组 """ """ x.__coerce__(y) <==> coerce(x, y) """ pass def __divmod__(self, y): """ 相除，得到商和余数组成的元组 """ """ x.__divmod__(y) <==> divmod(x, y) """ pass def __div__(self, y): """ x.__div__(y) <==> x/y """ pass def __float__(self): """ 转换为浮点类型 """ """ x.__float__() <==> float(x) """ pass def __floordiv__(self, y): """ x.__floordiv__(y) <==> x//y """ pass def __format__(self, *args, **kwargs): # real signature unknown pass def __getattribute__(self, name): """ x.__getattribute__('name') <==> x.name """ pass def __getnewargs__(self, *args, **kwargs): # real signature unknown """ 内部调用 __new__方法或创建对象时传入参数使用 """ pass def __hash__(self): """如果对象object为哈希表类型，返回对象object的哈希值。哈希值为整数。在字典查找中，哈希值用于快速比较字典的键。两个数值如果相等，则哈希值也相等。""" """ x.__hash__() <==> hash(x) """ pass def __hex__(self): """ 返回当前数的 十六进制 表示 """ """ x.__hex__() <==> hex(x) """ pass def __index__(self): """ 用于切片，数字无意义 """ """ x[y:z] <==> x[y.__index__():z.__index__()] """ pass def __init__(self, x, base=10): # known special case of int.__init__ """ 构造方法，执行 x = 123 或 x = int(10) 时，自动调用，暂时忽略 """ """ int(x=0) -> int or long int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments are given. If x is floating point, the conversion truncates towards zero. If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or Unicode object representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int('0b100', base=0) 4 # (copied from class doc) """ pass def __int__(self): """ 转换为整数 """ """ x.__int__() <==> int(x) """ pass def __invert__(self): """ x.__invert__() <==> ~x """ pass def __long__(self): """ 转换为长整数 """ """ x.__long__() <==> long(x) """ pass def __lshift__(self, y): """ x.__lshift__(y) <==> x<<y """ pass def __mod__(self, y): """ x.__mod__(y) <==> x%y """ pass def __mul__(self, y): """ x.__mul__(y) <==> x*y """ pass def __neg__(self): """ x.__neg__() <==> -x """ pass @staticmethod # known case of __new__ def __new__(S, *more): """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __nonzero__(self): """ x.__nonzero__() <==> x != 0 """ pass def __oct__(self): """ 返回改值的 八进制 表示 """ """ x.__oct__() <==> oct(x) """ pass def __or__(self, y): """ x.__or__(y) <==> x|y """ pass def __pos__(self): """ x.__pos__() <==> +x """ pass def __pow__(self, y, z=None): """ 幂，次方 """ """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """ pass def __radd__(self, y): """ x.__radd__(y) <==> y+x """ pass def __rand__(self, y): """ x.__rand__(y) <==> y&x """ pass def __rdivmod__(self, y): """ x.__rdivmod__(y) <==> divmod(y, x) """ pass def __rdiv__(self, y): """ x.__rdiv__(y) <==> y/x """ pass def __repr__(self): """转化为解释器可读取的形式 """ """ x.__repr__() <==> repr(x) """ pass def __str__(self): """转换为人阅读的形式，如果没有适于人阅读的解释形式的话，则返回解释器课阅读的形式""" """ x.__str__() <==> str(x) """ pass def __rfloordiv__(self, y): """ x.__rfloordiv__(y) <==> y//x """ pass def __rlshift__(self, y): """ x.__rlshift__(y) <==> y<<x """ pass def __rmod__(self, y): """ x.__rmod__(y) <==> y%x """ pass def __rmul__(self, y): """ x.__rmul__(y) <==> y*x """ pass def __ror__(self, y): """ x.__ror__(y) <==> y|x """ pass def __rpow__(self, x, z=None): """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """ pass def __rrshift__(self, y): """ x.__rrshift__(y) <==> y>>x """ pass def __rshift__(self, y): """ x.__rshift__(y) <==> x>>y """ pass def __rsub__(self, y): """ x.__rsub__(y) <==> y-x """ pass def __rtruediv__(self, y): """ x.__rtruediv__(y) <==> y/x """ pass def __rxor__(self, y): """ x.__rxor__(y) <==> y^x """ pass def __sub__(self, y): """ x.__sub__(y) <==> x-y """ pass def __truediv__(self, y): """ x.__truediv__(y) <==> x/y """ pass def __trunc__(self, *args, **kwargs): """ 返回数值被截取为整形的值，在整形中无意义 """ pass def __xor__(self, y): """ x.__xor__(y) <==> x^y """ pass denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 分母 = 1 """ """the denominator of a rational number in lowest terms""" imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 虚数，无意义 """ """the imaginary part of a complex number""" numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 分子 = 数字大小 """ """the numerator of a rational number in lowest terms""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 实属，无意义 """ """the real part of a complex number"""
二、长整型
可能如：2147483649、9223372036854775807
每个长整型都具备如下功能：
1 class long(object): 2 """ 3 long(x=0) -> long 4 long(x, base=10) -> long 5 6 Convert a number or string to a long integer, or return 0L if no arguments 7 are given. If x is floating point, the conversion truncates towards zero. 8 9 If x is not a number or if base is given, then x must be a string or 10 Unicode object representing an integer literal in the given base. The 11 literal can be preceded by '+' or '-' and be surrounded by whitespace. 12 The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to 13 interpret the base from the string as an integer literal. 14 >>> int('0b100', base=0) 15 4L 16 """ 17 def bit_length(self): # real signature unknown; restored from __doc__ 18 """ 19 long.bit_length() -> int or long 20 21 Number of bits necessary to represent self in binary. 22 >>> bin(37L) 23 '0b100101' 24 >>> (37L).bit_length() 25 """ 26 return 0 27 28 def conjugate(self, *args, **kwargs): # real signature unknown 29 """ Returns self, the complex conjugate of any long. """ 30 pass 31 32 def __abs__(self): # real signature unknown; restored from __doc__ 33 """ x.__abs__() <==> abs(x) """ 34 pass 35 36 def __add__(self, y): # real signature unknown; restored from __doc__ 37 """ x.__add__(y) <==> x+y """ 38 pass 39 40 def __and__(self, y): # real signature unknown; restored from __doc__ 41 """ x.__and__(y) <==> x&y """ 42 pass 43 44 def __cmp__(self, y): # real signature unknown; restored from __doc__ 45 """ x.__cmp__(y) <==> cmp(x,y) """ 46 pass 47 48 def __coerce__(self, y): # real signature unknown; restored from __doc__ 49 """ x.__coerce__(y) <==> coerce(x, y) """ 50 pass 51 52 def __divmod__(self, y): # real signature unknown; restored from __doc__ 53 """ x.__divmod__(y) <==> divmod(x, y) """ 54 pass 55 56 def __div__(self, y): # real signature unknown; restored from __doc__ 57 """ x.__div__(y) <==> x/y """ 58 pass 59 60 def __float__(self): # real signature unknown; restored from __doc__ 61 """ x.__float__() <==> float(x) """ 62 pass 63 64 def __floordiv__(self, y): # real signature unknown; restored from __doc__ 65 """ x.__floordiv__(y) <==> x//y """ 66 pass 67 68 def __format__(self, *args, **kwargs): # real signature unknown 69 pass 70 71 def __getattribute__(self, name): # real signature unknown; restored from __doc__ 72 """ x.__getattribute__('name') <==> x.name """ 73 pass 74 75 def __getnewargs__(self, *args, **kwargs): # real signature unknown 76 pass 77 78 def __hash__(self): # real signature unknown; restored from __doc__ 79 """ x.__hash__() <==> hash(x) """ 80 pass 81 82 def __hex__(self): # real signature unknown; restored from __doc__ 83 """ x.__hex__() <==> hex(x) """ 84 pass 85 86 def __index__(self): # real signature unknown; restored from __doc__ 87 """ x[y:z] <==> x[y.__index__():z.__index__()] """ 88 pass 89 90 def __init__(self, x=0): # real signature unknown; restored from __doc__ 91 pass 92 93 def __int__(self): # real signature unknown; restored from __doc__ 94 """ x.__int__() <==> int(x) """ 95 pass 96 97 def __invert__(self): # real signature unknown; restored from __doc__ 98 """ x.__invert__() <==> ~x """ 99 pass 100 101 def __long__(self): # real signature unknown; restored from __doc__ 102 """ x.__long__() <==> long(x) """ 103 pass 104 105 def __lshift__(self, y): # real signature unknown; restored from __doc__ 106 """ x.__lshift__(y) <==> x<<y """ 107 pass 108 109 def __mod__(self, y): # real signature unknown; restored from __doc__ 110 """ x.__mod__(y) <==> x%y """ 111 pass 112 113 def __mul__(self, y): # real signature unknown; restored from __doc__ 114 """ x.__mul__(y) <==> x*y """ 115 pass 116 117 def __neg__(self): # real signature unknown; restored from __doc__ 118 """ x.__neg__() <==> -x """ 119 pass 120 121 @staticmethod # known case of __new__ 122 def __new__(S, *more): # real signature unknown; restored from __doc__ 123 """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ 124 pass 125 126 def __nonzero__(self): # real signature unknown; restored from __doc__ 127 """ x.__nonzero__() <==> x != 0 """ 128 pass 129 130 def __oct__(self): # real signature unknown; restored from __doc__ 131 """ x.__oct__() <==> oct(x) """ 132 pass 133 134 def __or__(self, y): # real signature unknown; restored from __doc__ 135 """ x.__or__(y) <==> x|y """ 136 pass 137 138 def __pos__(self): # real signature unknown; restored from __doc__ 139 """ x.__pos__() <==> +x """ 140 pass 141 142 def __pow__(self, y, z=None): # real signature unknown; restored from __doc__ 143 """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """ 144 pass 145 146 def __radd__(self, y): # real signature unknown; restored from __doc__ 147 """ x.__radd__(y) <==> y+x """ 148 pass 149 150 def __rand__(self, y): # real signature unknown; restored from __doc__ 151 """ x.__rand__(y) <==> y&x """ 152 pass 153 154 def __rdivmod__(self, y): # real signature unknown; restored from __doc__ 155 """ x.__rdivmod__(y) <==> divmod(y, x) """ 156 pass 157 158 def __rdiv__(self, y): # real signature unknown; restored from __doc__ 159 """ x.__rdiv__(y) <==> y/x """ 160 pass 161 162 def __repr__(self): # real signature unknown; restored from __doc__ 163 """ x.__repr__() <==> repr(x) """ 164 pass 165 166 def __rfloordiv__(self, y): # real signature unknown; restored from __doc__ 167 """ x.__rfloordiv__(y) <==> y//x """ 168 pass 169 170 def __rlshift__(self, y): # real signature unknown; restored from __doc__ 171 """ x.__rlshift__(y) <==> y<<x """ 172 pass 173 174 def __rmod__(self, y): # real signature unknown; restored from __doc__ 175 """ x.__rmod__(y) <==> y%x """ 176 pass 177 178 def __rmul__(self, y): # real signature unknown; restored from __doc__ 179 """ x.__rmul__(y) <==> y*x """ 180 pass 181 182 def __ror__(self, y): # real signature unknown; restored from __doc__ 183 """ x.__ror__(y) <==> y|x """ 184 pass 185 186 def __rpow__(self, x, z=None): # real signature unknown; restored from __doc__ 187 """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """ 188 pass 189 190 def __rrshift__(self, y): # real signature unknown; restored from __doc__ 191 """ x.__rrshift__(y) <==> y>>x """ 192 pass 193 194 def __rshift__(self, y): # real signature unknown; restored from __doc__ 195 """ x.__rshift__(y) <==> x>>y """ 196 pass 197 198 def __rsub__(self, y): # real signature unknown; restored from __doc__ 199 """ x.__rsub__(y) <==> y-x """ 200 pass 201 202 def __rtruediv__(self, y): # real signature unknown; restored from __doc__ 203 """ x.__rtruediv__(y) <==> y/x """ 204 pass 205 206 def __rxor__(self, y): # real signature unknown; restored from __doc__ 207 """ x.__rxor__(y) <==> y^x """ 208 pass 209 210 def __sizeof__(self, *args, **kwargs): # real signature unknown 211 """ Returns size in memory, in bytes """ 212 pass 213 214 def __str__(self): # real signature unknown; restored from __doc__ 215 """ x.__str__() <==> str(x) """ 216 pass 217 218 def __sub__(self, y): # real signature unknown; restored from __doc__ 219 """ x.__sub__(y) <==> x-y """ 220 pass 221 222 def __truediv__(self, y): # real signature unknown; restored from __doc__ 223 """ x.__truediv__(y) <==> x/y """ 224 pass 225 226 def __trunc__(self, *args, **kwargs): # real signature unknown 227 """ Truncating an Integral returns itself. """ 228 pass 229 230 def __xor__(self, y): # real signature unknown; restored from __doc__ 231 """ x.__xor__(y) <==> x^y """ 232 pass 233 234 denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 235 """the denominator of a rational number in lowest terms""" 236 237 imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 238 """the imaginary part of a complex number""" 239 240 numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 241 """the numerator of a rational number in lowest terms""" 242 243 real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 244 """the real part of a complex number""" 245 246 long
三、浮点型
如：3.14、2.88
每个浮点型都具备如下功能：
1 class float(object): 2 """ 3 float(x) -> floating point number 4 5 Convert a string or number to a floating point number, if possible. 6 """ 7 def as_integer_ratio(self): 8 """ 获取改值的最简比 """ 9 """ 10 float.as_integer_ratio() -> (int, int) 11 12 Return a pair of integers, whose ratio is exactly equal to the original 13 float and with a positive denominator. 14 Raise OverflowError on infinities and a ValueError on NaNs. 15 16 >>> (10.0).as_integer_ratio() 17 (10, 1) 18 >>> (0.0).as_integer_ratio() 19 (0, 1) 20 >>> (-.25).as_integer_ratio() 21 (-1, 4) 22 """ 23 pass 24 25 def conjugate(self, *args, **kwargs): # real signature unknown 26 """ Return self, the complex conjugate of any float. """ 27 pass 28 29 def fromhex(self, string): 30 """ 将十六进制字符串转换成浮点型 """ 31 """ 32 float.fromhex(string) -> float 33 34 Create a floating-point number from a hexadecimal string. 35 >>> float.fromhex('0x1.ffffp10') 36 2047.984375 37 >>> float.fromhex('-0x1p-1074') 38 -4.9406564584124654e-324 39 """ 40 return 0.0 41 42 def hex(self): 43 """ 返回当前值的 16 进制表示 """ 44 """ 45 float.hex() -> string 46 47 Return a hexadecimal representation of a floating-point number. 48 >>> (-0.1).hex() 49 '-0x1.999999999999ap-4' 50 >>> 3.14159.hex() 51 '0x1.921f9f01b866ep+1' 52 """ 53 return "" 54 55 def is_integer(self, *args, **kwargs): # real signature unknown 56 """ Return True if the float is an integer. """ 57 pass 58 59 def __abs__(self): 60 """ x.__abs__() <==> abs(x) """ 61 pass 62 63 def __add__(self, y): 64 """ x.__add__(y) <==> x+y """ 65 pass 66 67 def __coerce__(self, y): 68 """ x.__coerce__(y) <==> coerce(x, y) """ 69 pass 70 71 def __divmod__(self, y): 72 """ x.__divmod__(y) <==> divmod(x, y) """ 73 pass 74 75 def __div__(self, y): 76 """ x.__div__(y) <==> x/y """ 77 pass 78 79 def __eq__(self, y): 80 """ x.__eq__(y) <==> x==y """ 81 pass 82 83 def __float__(self): 84 """ x.__float__() <==> float(x) """ 85 pass 86 87 def __floordiv__(self, y): 88 """ x.__floordiv__(y) <==> x//y """ 89 pass 90 91 def __format__(self, format_spec): 92 """ 93 float.__format__(format_spec) -> string 94 95 Formats the float according to format_spec. 96 """ 97 return "" 98 99 def __getattribute__(self, name): 100 """ x.__getattribute__('name') <==> x.name """ 101 pass 102 103 def __getformat__(self, typestr): 104 """ 105 float.__getformat__(typestr) -> string 106 107 You probably don't want to use this function. It exists mainly to be 108 used in Python's test suite. 109 110 typestr must be 'double' or 'float'. This function returns whichever of 111 'unknown', 'IEEE, big-endian' or 'IEEE, little-endian' best describes the 112 format of floating point numbers used by the C type named by typestr. 113 """ 114 return "" 115 116 def __getnewargs__(self, *args, **kwargs): # real signature unknown 117 pass 118 119 def __ge__(self, y): 120 """ x.__ge__(y) <==> x>=y """ 121 pass 122 123 def __gt__(self, y): 124 """ x.__gt__(y) <==> x>y """ 125 pass 126 127 def __hash__(self): 128 """ x.__hash__() <==> hash(x) """ 129 pass 130 131 def __init__(self, x): 132 pass 133 134 def __int__(self): 135 """ x.__int__() <==> int(x) """ 136 pass 137 138 def __le__(self, y): 139 """ x.__le__(y) <==> x<=y """ 140 pass 141 142 def __long__(self): 143 """ x.__long__() <==> long(x) """ 144 pass 145 146 def __lt__(self, y): 147 """ x.__lt__(y) <==> x<y """ 148 pass 149 150 def __mod__(self, y): 151 """ x.__mod__(y) <==> x%y """ 152 pass 153 154 def __mul__(self, y): 155 """ x.__mul__(y) <==> x*y """ 156 pass 157 158 def __neg__(self): 159 """ x.__neg__() <==> -x """ 160 pass 161 162 @staticmethod # known case of __new__ 163 def __new__(S, *more): 164 """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ 165 pass 166 167 def __ne__(self, y): 168 """ x.__ne__(y) <==> x!=y """ 169 pass 170 171 def __nonzero__(self): 172 """ x.__nonzero__() <==> x != 0 """ 173 pass 174 175 def __pos__(self): 176 """ x.__pos__() <==> +x """ 177 pass 178 179 def __pow__(self, y, z=None): 180 """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """ 181 pass 182 183 def __radd__(self, y): 184 """ x.__radd__(y) <==> y+x """ 185 pass 186 187 def __rdivmod__(self, y): 188 """ x.__rdivmod__(y) <==> divmod(y, x) """ 189 pass 190 191 def __rdiv__(self, y): 192 """ x.__rdiv__(y) <==> y/x """ 193 pass 194 195 def __repr__(self): 196 """ x.__repr__() <==> repr(x) """ 197 pass 198 199 def __rfloordiv__(self, y): 200 """ x.__rfloordiv__(y) <==> y//x """ 201 pass 202 203 def __rmod__(self, y): 204 """ x.__rmod__(y) <==> y%x """ 205 pass 206 207 def __rmul__(self, y): 208 """ x.__rmul__(y) <==> y*x """ 209 pass 210 211 def __rpow__(self, x, z=None): 212 """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """ 213 pass 214 215 def __rsub__(self, y): 216 """ x.__rsub__(y) <==> y-x """ 217 pass 218 219 def __rtruediv__(self, y): 220 """ x.__rtruediv__(y) <==> y/x """ 221 pass 222 223 def __setformat__(self, typestr, fmt): 224 """ 225 float.__setformat__(typestr, fmt) -> None 226 227 You probably don't want to use this function. It exists mainly to be 228 used in Python's test suite. 229 230 typestr must be 'double' or 'float'. fmt must be one of 'unknown', 231 'IEEE, big-endian' or 'IEEE, little-endian', and in addition can only be 232 one of the latter two if it appears to match the underlying C reality. 233 234 Override the automatic determination of C-level floating point type. 235 This affects how floats are converted to and from binary strings. 236 """ 237 pass 238 239 def __str__(self): 240 """ x.__str__() <==> str(x) """ 241 pass 242 243 def __sub__(self, y): 244 """ x.__sub__(y) <==> x-y """ 245 pass 246 247 def __truediv__(self, y): 248 """ x.__truediv__(y) <==> x/y """ 249 pass 250 251 def __trunc__(self, *args, **kwargs): # real signature unknown 252 """ Return the Integral closest to x between 0 and x. """ 253 pass 254 255 imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 256 """the imaginary part of a complex number""" 257 258 real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 259 """the real part of a complex number""" 260 261 float
四、字符串
如：'Jim'、'Jade'
每个字符串都具备如下功能：
1 class str(basestring): 2 """ 3 str(object='') -> string 4 5 Return a nice string representation of the object. 6 If the argument is a string, the return value is the same object. 7 """ 8 def capitalize(self): 9 """ 首字母变大写 """ 10 """ 11 S.capitalize() -> string 12 13 Return a copy of the string S with only its first character 14 capitalized. 15 """ 16 return "" 17 18 def center(self, width, fillchar=None): 19 """ 内容居中，width：总长度；fillchar：空白处填充内容，默认无 """ 20 """ 21 S.center(width[, fillchar]) -> string 22 23 Return S centered in a string of length width. Padding is 24 done using the specified fill character (default is a space) 25 """ 26 return "" 27 28 def count(self, sub, start=None, end=None): 29 """ 子序列个数 """ 30 """ 31 S.count(sub[, start[, end]]) -> int 32 33 Return the number of non-overlapping occurrences of substring sub in 34 string S[start:end]. Optional arguments start and end are interpreted 35 as in slice notation. 36 """ 37 return 0 38 39 def decode(self, encoding=None, errors=None): 40 """ 解码 """ 41 """ 42 S.decode([encoding[,errors]]) -> object 43 44 Decodes S using the codec registered for encoding. encoding defaults 45 to the default encoding. errors may be given to set a different error 46 handling scheme. Default is 'strict' meaning that encoding errors raise 47 a UnicodeDecodeError. Other possible values are 'ignore' and 'replace' 48 as well as any other name registered with codecs.register_error that is 49 able to handle UnicodeDecodeErrors. 50 """ 51 return object() 52 53 def encode(self, encoding=None, errors=None): 54 """ 编码，针对unicode """ 55 """ 56 S.encode([encoding[,errors]]) -> object 57 58 Encodes S using the codec registered for encoding. encoding defaults 59 to the default encoding. errors may be given to set a different error 60 handling scheme. Default is 'strict' meaning that encoding errors raise 61 a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and 62 'xmlcharrefreplace' as well as any other name registered with 63 codecs.register_error that is able to handle UnicodeEncodeErrors. 64 """ 65 return object() 66 67 def endswith(self, suffix, start=None, end=None): 68 """ 是否以 xxx 结束 """ 69 """ 70 S.endswith(suffix[, start[, end]]) -> bool 71 72 Return True if S ends with the specified suffix, False otherwise. 73 With optional start, test S beginning at that position. 74 With optional end, stop comparing S at that position. 75 suffix can also be a tuple of strings to try. 76 """ 77 return False 78 79 def expandtabs(self, tabsize=None): 80 """ 将tab转换成空格，默认一个tab转换成8个空格 """ 81 """ 82 S.expandtabs([tabsize]) -> string 83 84 Return a copy of S where all tab characters are expanded using spaces. 85 If tabsize is not given, a tab size of 8 characters is assumed. 86 """ 87 return "" 88 89 def find(self, sub, start=None, end=None): 90 """ 寻找子序列位置，如果没找到，返回 -1 """ 91 """ 92 S.find(sub [,start [,end]]) -> int 93 94 Return the lowest index in S where substring sub is found, 95 such that sub is contained within S[start:end]. Optional 96 arguments start and end are interpreted as in slice notation. 97 98 Return -1 on failure. 99 """ 100 return 0 101 102 def format(*args, **kwargs): # known special case of str.format 103 """ 字符串格式化，动态参数，将函数式编程时细说 """ 104 """ 105 S.format(*args, **kwargs) -> string 106 107 Return a formatted version of S, using substitutions from args and kwargs. 108 The substitutions are identified by braces ('{' and '}'). 109 """ 110 pass 111 112 def index(self, sub, start=None, end=None): 113 """ 子序列位置，如果没找到，报错 """ 114 S.index(sub [,start [,end]]) -> int 115 116 Like S.find() but raise ValueError when the substring is not found. 117 """ 118 return 0 119 120 def isalnum(self): 121 """ 是否是字母和数字 """ 122 """ 123 S.isalnum() -> bool 124 125 Return True if all characters in S are alphanumeric 126 and there is at least one character in S, False otherwise. 127 """ 128 return False 129 130 def isalpha(self): 131 """ 是否是字母 """ 132 """ 133 S.isalpha() -> bool 134 135 Return True if all characters in S are alphabetic 136 and there is at least one character in S, False otherwise. 137 """ 138 return False 139 140 def isdigit(self): 141 """ 是否是数字 """ 142 """ 143 S.isdigit() -> bool 144 145 Return True if all characters in S are digits 146 and there is at least one character in S, False otherwise. 147 """ 148 return False 149 150 def islower(self): 151 """ 是否小写 """ 152 """ 153 S.islower() -> bool 154 155 Return True if all cased characters in S are lowercase and there is 156 at least one cased character in S, False otherwise. 157 """ 158 return False 159 160 def isspace(self): 161 """ 162 S.isspace() -> bool 163 164 Return True if all characters in S are whitespace 165 and there is at least one character in S, False otherwise. 166 """ 167 return False 168 169 def istitle(self): 170 """ 171 S.istitle() -> bool 172 173 Return True if S is a titlecased string and there is at least one 174 character in S, i.e. uppercase characters may only follow uncased 175 characters and lowercase characters only cased ones. Return False 176 otherwise. 177 """ 178 return False 179 180 def isupper(self): 181 """ 182 S.isupper() -> bool 183 184 Return True if all cased characters in S are uppercase and there is 185 at least one cased character in S, False otherwise. 186 """ 187 return False 188 189 def join(self, iterable): 190 """ 连接 """ 191 """ 192 S.join(iterable) -> string 193 194 Return a string which is the concatenation of the strings in the 195 iterable. The separator between elements is S. 196 """ 197 return "" 198 199 def ljust(self, width, fillchar=None): 200 """ 内容左对齐，右侧填充 """ 201 """ 202 S.ljust(width[, fillchar]) -> string 203 204 Return S left-justified in a string of length width. Padding is 205 done using the specified fill character (default is a space). 206 """ 207 return "" 208 209 def lower(self): 210 """ 变小写 """ 211 """ 212 S.lower() -> string 213 214 Return a copy of the string S converted to lowercase. 215 """ 216 return "" 217 218 def lstrip(self, chars=None): 219 """ 移除左侧空白 """ 220 """ 221 S.lstrip([chars]) -> string or unicode 222 223 Return a copy of the string S with leading whitespace removed. 224 If chars is given and not None, remove characters in chars instead. 225 If chars is unicode, S will be converted to unicode before stripping 226 """ 227 return "" 228 229 def partition(self, sep): 230 """ 分割，前，中，后三部分 """ 231 """ 232 S.partition(sep) -> (head, sep, tail) 233 234 Search for the separator sep in S, and return the part before it, 235 the separator itself, and the part after it. If the separator is not 236 found, return S and two empty strings. 237 """ 238 pass 239 240 def replace(self, old, new, count=None): 241 """ 替换 """ 242 """ 243 S.replace(old, new[, count]) -> string 244 245 Return a copy of string S with all occurrences of substring 246 old replaced by new. If the optional argument count is 247 given, only the first count occurrences are replaced. 248 """ 249 return "" 250 251 def rfind(self, sub, start=None, end=None): 252 """ 253 S.rfind(sub [,start [,end]]) -> int 254 255 Return the highest index in S where substring sub is found, 256 such that sub is contained within S[start:end]. Optional 257 arguments start and end are interpreted as in slice notation. 258 259 Return -1 on failure. 260 """ 261 return 0 262 263 def rindex(self, sub, start=None, end=None): 264 """ 265 S.rindex(sub [,start [,end]]) -> int 266 267 Like S.rfind() but raise ValueError when the substring is not found. 268 """ 269 return 0 270 271 def rjust(self, width, fillchar=None): 272 """ 273 S.rjust(width[, fillchar]) -> string 274 275 Return S right-justified in a string of length width. Padding is 276 done using the specified fill character (default is a space) 277 """ 278 return "" 279 280 def rpartition(self, sep): 281 """ 282 S.rpartition(sep) -> (head, sep, tail) 283 284 Search for the separator sep in S, starting at the end of S, and return 285 the part before it, the separator itself, and the part after it. If the 286 separator is not found, return two empty strings and S. 287 """ 288 pass 289 290 def rsplit(self, sep=None, maxsplit=None): 291 """ 292 S.rsplit([sep [,maxsplit]]) -> list of strings 293 294 Return a list of the words in the string S, using sep as the 295 delimiter string, starting at the end of the string and working 296 to the front. If maxsplit is given, at most maxsplit splits are 297 done. If sep is not specified or is None, any whitespace string 298 is a separator. 299 """ 300 return [] 301 302 def rstrip(self, chars=None): 303 """ 304 S.rstrip([chars]) -> string or unicode 305 306 Return a copy of the string S with trailing whitespace removed. 307 If chars is given and not None, remove characters in chars instead. 308 If chars is unicode, S will be converted to unicode before stripping 309 """ 310 return "" 311 312 def split(self, sep=None, maxsplit=None): 313 """ 分割， maxsplit最多分割几次 """ 314 """ 315 S.split([sep [,maxsplit]]) -> list of strings 316 317 Return a list of the words in the string S, using sep as the 318 delimiter string. If maxsplit is given, at most maxsplit 319 splits are done. If sep is not specified or is None, any 320 whitespace string is a separator and empty strings are removed 321 from the result. 322 """ 323 return [] 324 325 def splitlines(self, keepends=False): 326 """ 根据换行分割 """ 327 """ 328 S.splitlines(keepends=False) -> list of strings 329 330 Return a list of the lines in S, breaking at line boundaries. 331 Line breaks are not included in the resulting list unless keepends 332 is given and true. 333 """ 334 return [] 335 336 def startswith(self, prefix, start=None, end=None): 337 """ 是否起始 """ 338 """ 339 S.startswith(prefix[, start[, end]]) -> bool 340 341 Return True if S starts with the specified prefix, False otherwise. 342 With optional start, test S beginning at that position. 343 With optional end, stop comparing S at that position. 344 prefix can also be a tuple of strings to try. 345 """ 346 return False 347 348 def strip(self, chars=None): 349 """ 移除两段空白 """ 350 """ 351 S.strip([chars]) -> string or unicode 352 353 Return a copy of the string S with leading and trailing 354 whitespace removed. 355 If chars is given and not None, remove characters in chars instead. 356 If chars is unicode, S will be converted to unicode before stripping 357 """ 358 return "" 359 360 def swapcase(self): 361 """ 大写变小写，小写变大写 """ 362 """ 363 S.swapcase() -> string 364 365 Return a copy of the string S with uppercase characters 366 converted to lowercase and vice versa. 367 """ 368 return "" 369 370 def title(self): 371 """ 372 S.title() -> string 373 374 Return a titlecased version of S, i.e. words start with uppercase 375 characters, all remaining cased characters have lowercase. 376 """ 377 return "" 378 379 def translate(self, table, deletechars=None): 380 """ 381 转换，需要先做一个对应表，最后一个表示删除字符集合 382 intab = "aeiou" 383 outtab = "12345" 384 trantab = maketrans(intab, outtab) 385 str = "this is string example....wow!!!" 386 print str.translate(trantab, 'xm') 387 """ 388 389 """ 390 S.translate(table [,deletechars]) -> string 391 392 Return a copy of the string S, where all characters occurring 393 in the optional argument deletechars are removed, and the 394 remaining characters have been mapped through the given 395 translation table, which must be a string of length 256 or None. 396 If the table argument is None, no translation is applied and 397 the operation simply removes the characters in deletechars. 398 """ 399 return "" 400 401 def upper(self): 402 """ 403 S.upper() -> string 404 405 Return a copy of the string S converted to uppercase. 406 """ 407 return "" 408 409 def zfill(self, width): 410 """方法返回指定长度的字符串，原字符串右对齐，前面填充0。""" 411 """ 412 S.zfill(width) -> string 413 414 Pad a numeric string S with zeros on the left, to fill a field 415 of the specified width. The string S is never truncated. 416 """ 417 return "" 418 419 def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown 420 pass 421 422 def _formatter_parser(self, *args, **kwargs): # real signature unknown 423 pass 424 425 def __add__(self, y): 426 """ x.__add__(y) <==> x+y """ 427 pass 428 429 def __contains__(self, y): 430 """ x.__contains__(y) <==> y in x """ 431 pass 432 433 def __eq__(self, y): 434 """ x.__eq__(y) <==> x==y """ 435 pass 436 437 def __format__(self, format_spec): 438 """ 439 S.__format__(format_spec) -> string 440 441 Return a formatted version of S as described by format_spec. 442 """ 443 return "" 444 445 def __getattribute__(self, name): 446 """ x.__getattribute__('name') <==> x.name """ 447 pass 448 449 def __getitem__(self, y): 450 """ x.__getitem__(y) <==> x[y] """ 451 pass 452 453 def __getnewargs__(self, *args, **kwargs): # real signature unknown 454 pass 455 456 def __getslice__(self, i, j): 457 """ 458 x.__getslice__(i, j) <==> x[i:j] 459 460 Use of negative indices is not supported. 461 """ 462 pass 463 464 def __ge__(self, y): 465 """ x.__ge__(y) <==> x>=y """ 466 pass 467 468 def __gt__(self, y): 469 """ x.__gt__(y) <==> x>y """ 470 pass 471 472 def __hash__(self): 473 """ x.__hash__() <==> hash(x) """ 474 pass 475 476 def __init__(self, string=''): # known special case of str.__init__ 477 """ 478 str(object='') -> string 479 480 Return a nice string representation of the object. 481 If the argument is a string, the return value is the same object. 482 # (copied from class doc) 483 """ 484 pass 485 486 def __len__(self): 487 """ x.__len__() <==> len(x) """ 488 pass 489 490 def __le__(self, y): 491 """ x.__le__(y) <==> x<=y """ 492 pass 493 494 def __lt__(self, y): 495 """ x.__lt__(y) <==> x<y """ 496 pass 497 498 def __mod__(self, y): 499 """ x.__mod__(y) <==> x%y """ 500 pass 501 502 def __mul__(self, n): 503 """ x.__mul__(n) <==> x*n """ 504 pass 505 506 @staticmethod # known case of __new__ 507 def __new__(S, *more): 508 """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ 509 pass 510 511 def __ne__(self, y): 512 """ x.__ne__(y) <==> x!=y """ 513 pass 514 515 def __repr__(self): 516 """ x.__repr__() <==> repr(x) """ 517 pass 518 519 def __rmod__(self, y): 520 """ x.__rmod__(y) <==> y%x """ 521 pass 522 523 def __rmul__(self, n): 524 """ x.__rmul__(n) <==> n*x """ 525 pass 526 527 def __sizeof__(self): 528 """ S.__sizeof__() -> size of S in memory, in bytes """ 529 pass 530 531 def __str__(self): 532 """ x.__str__() <==> str(x) """ 533 pass 534 535 str 536 537 str
在最新的Python3版本中，字符串是用Unicode表示的，对于单个字符我们可以用Python提供的ord()函数或字符的整数编码（编码的十进制），用chr()吧编码转换为对应的字符
>>> ord('a')
97
>>> ord('王')
29579
>>> chr(29579)
'王'
注：编码；字符串的乘法；字符串和格式化
1.center居中对齐
1 1 def center(self, width, fillchar=None): # real signature unknown; restored from __doc__ 2 2 """ 3 3 S.center(width[, fillchar]) -> str 4 4 返回新的字符串对象，居中对齐 5 5 width：宽度，返回的字符串长度 6 6 fillchar：填充字符 7 7 Return S centered in a string of length width. Padding is 8 8 done using the specified fill character (default is a space) 9 9 """ 10 10 return ""
>>> str.center(25,'*')
'********Hello man********'
2.count显示字符出现的次数
1 def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 2 """ 3 S.count(sub[, start[, end]]) -> int 4 # 返回整形，子串出现的次数 5 sub：查询的子串 6 start：开始索引 7 end：结束索引 8 9 Return the number of non-overlapping occurrences of substring sub in 10 string S[start:end]. Optional arguments start and end are 11 interpreted as in slice notation. 12 """ 13 return 0
>>> str.count("l")
2
>>> str.count("l",3)
1
>>> str.count("l",5,7)
0
3.encode（返回指定编码的字节流）
1 def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__ 2 """ 3 S.encode(encoding='utf-8', errors='strict') -> bytes 4 返回指定编码的字节流（老师说是uncode编码） 5 6 Encode S using the codec registered for encoding. Default encoding 7 is 'utf-8'. errors may be given to set a different error 8 handling scheme. Default is 'strict' meaning that encoding errors raise 9 a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and 10 'xmlcharrefreplace' as well as any other name registered with 11 codecs.register_error that can handle UnicodeEncodeErrors. 12 """ 13 return b""
>>> 'ABC'.encode('ascii')
b'ABC'
>>> 'ABC'.encode('utf-8')
b'ABC'
>>> '王健'.encode('ascii')
Traceback (most recent call last):
File "<input>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-1: ordinal not in range(128)
>>> '王健'.encode('utf-8')
b'xe7x8ex8bxe5x81xa5'
4.startwith,endwith(判断字符开头及结尾)
1 def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__ 2 """ 3 S.startswith(prefix[, start[, end]]) -> bool 4 5 Return True if S starts with the specified prefix, False otherwise. 6 With optional start, test S beginning at that position. 7 With optional end, stop comparing S at that position. 8 prefix can also be a tuple of strings to try. 9 """ 10 return False 11 12 def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__ 13 """ 14 S.endswith(suffix[, start[, end]]) -> bool 15 16 Return True if S ends with the specified suffix, False otherwise. 17 With optional start, test S beginning at that position. 18 With optional end, stop comparing S at that position. 19 suffix can also be a tuple of strings to try. 20 """ 21 return False
>>> str.startswith('Hello')
True
>>> str.endswith('an')
True
5.expandtabs（设定制表符的宽度）
1 def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__ 2 """ 3 S.expandtabs(tabsize=8) -> str 4 返回新的字符串对象，设定制表符的宽度 5 Return a copy of S where all tab characters are expanded using spaces. 6 If tabsize is not given, a tab size of 8 characters is assumed. 7 """ 8 return ""
>>> str = 'hello Jason'
>>> str
'hello Jason'
>>> print(str)
hello Jason
>>> print(str.expandtabs())
hello Jason
>>> print(str.expandtabs(8))
hello Jason
>>> print(str.expandtabs(16))
hello Jason
6.find(查找子串）
1 >>> str = 'hello Jason' 2 >>> str 3 'hello Jason' 4 >>> print(str) 5 hello Jason 6 >>> print(str.expandtabs()) 7 hello Jason 8 >>> print(str.expandtabs(8)) 9 hello Jason 10 >>> print(str.expandtabs(16)) 11 hello Jason
>>> str.find('h')
0
>>> str.find('x')
-1
7.format(格式化输出）
1 def format(*args, **kwargs): # known special case of str.format 2 """ 3 S.format(*args, **kwargs) -> str 4 格式化字符串，返回新的字符串对象，类似占位符 5 6 Return a formatted version of S, using substitutions from args and kwargs. 7 The substitutions are identified by braces ('{' and '}'). 8 """ 9 pass
>>> str = "hello {0}"
>>> str.format('Jason')
'hello Jason'
>>> str = "hello {0}{1}"
>>> str.format('Jason','!')
'hello Jason!'
>>> str = "hello {name}"
>>> str.format(name='Jason')
'hello Jason'
8.format_map（格式化输出）
def format_map(self, mapping): # real signature unknown; restored from __doc__ """ S.format_map(mapping) -> str 格式化字符串，返回新的字符串对象 mapping：字典对象，用来替换站位符 Return a formatted version of S, using substitutions from mapping. The substitutions are identified by braces ('{' and '}'). """ return ""
>>> str = "hello {name}"
>>> str.format_map({"name":"Jack"})
'hello Jack'
9.index（查找子串，返回子串的索引）
1 def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 2 """ 3 S.index(sub[, start[, end]]) -> int 4 查找子串，使用方法同find，不同是如果不存在会报错 5 Like S.find() but raise ValueError when the substring is not found. 6 """ 7 return 0
>>> str = 'Hello James'
>>> str.index('Hello')
0
>>> str.index('o')
4
>>> str.index('k')
Traceback (most recent call last):
File "<input>", line 1, in <module>
ValueError: substring not found
10.isdigit（判断是否由数字组成，同上）
def isdigit(self): # real signature unknown; restored from __doc__ """ S.isdigit() -> bool 判断是否由数字组成 Return True if all characters in S are digits and there is at least one character in S, False otherwise. """ return False
>>> str = '1234'
>>> str.isdigit()
True
>>> str = '1234.22'
>>> str.isdigit()
False
11.join（拼接序列）
1 def join(self, iterable): # real signature unknown; restored from __doc__ 2 """ 3 S.join(iterable) -> str 4 以当前字符串为分隔符，拼接序列对象（如列表、元祖等），返回新的字符串对象 5 iterable：要拼接的序列化对象 6 Return a string which is the concatenation of the strings in the 7 iterable. The separator between elements is S. 8 """ 9 return ""
>>> li = ['hi','Jason']
>>> '*'.join(li)
'hi*Jason'
12.ljust（左对齐）
1 def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__ 2 """ 3 S.ljust(width[, fillchar]) -> str 4 左对齐，返回新的字符串对象 5 width：新出的字符串对象宽度 6 fillchar：填充字符串，默认是空格 7 Return S left-justified in a Unicode string of length width. Padding is 8 done using the specified fill character (default is a space). 9 """ 10 return ""
>>> str = 'Jason'
>>> str.ljust(16,'*')
'Jason***********'
13.strip,lstrip(左),rstrip（右）（脱去的空格或自定子串）
1 def strip(self, chars=None): # real signature unknown; restored from __doc__ 2 """ 3 S.strip([chars]) -> str 4 5 Return a copy of the string S with leading and trailing 6 whitespace removed. 7 If chars is given and not None, remove characters in chars instead. 8 """ 9 return "" 10 def lstrip(self, chars=None): # real signature unknown; restored from __doc__ 11 """ 12 S.lstrip([chars]) -> str 13 脱去左侧的空格或自定子串 14 chars：要脱去的子串 15 Return a copy of the string S with leading whitespace removed. 16 If chars is given and not None, remove characters in chars instead. 17 """ 18 return ""
>>> str = ' Jason'
>>> str.strip()
'Jason'
>>> str = ' Jason'
>>> str.lstrip()
'Jason'
>>> str.rstrip()
' Jason'
14.maketrans和translate
def maketrans(self, *args, **kwargs): # real signature unknown """ Return a translation table usable for str.translate(). 创建translate对照表 If there is only one argument, it must be a dictionary mapping Unicode ordinals (integers) or characters to Unicode ordinals, strings or None. Character keys will be then converted to ordinals. If there are two arguments, they must be strings of equal length, and in the resulting dictionary, each character in x will be mapped to the character at the same position in y. If there is a third argument, it must be a string, whose characters will be mapped to None in the result. """ pass def translate(self, table): # real signature unknown; restored from __doc__ """ S.translate(table) -> str 通过对照表完成字符替换 table：对照表对象，maketrans返回的对象 Return a copy of the string S in which each character has been mapped through the given translation table. The table must implement lookup/indexing via __getitem__, for instance a dictionary or list, mapping Unicode ordinals to Unicode ordinals, strings, or None. If this operation raises LookupError, the character is left untouched. Characters mapped to None are deleted. """ return ""
>>> tranli =str.maketrans('23','yt')
>>> s = '123445'
>>> s.translate(tranli)
'1yt445
15.partition（返回分隔符分隔的元祖，从左侧开始查找）
1 def partition(self, sep): # real signature unknown; restored from __doc__ 2 """ 3 S.partition(sep) -> (head, sep, tail) 4 返回一个三个元素的元祖，第一个元素为分隔符左侧的子串，第二个元素为分隔符，第三个元素为分隔符右侧的子串 5 sep：分隔符 6 7 Search for the separator sep in S, and return the part before it, 8 the separator itself, and the part after it. If the separator is not 9 found, return S and two empty strings. 10 """ 11 pass
>>> str = "https://jsdd.com.cn"
>>> str.partition("//")
('https:', '//', 'jsdd.com.cn')
16.replace（子串替换）
1 def replace(self, old, new, count=None): # real signature unknown; restored from __doc__ 2 """ 3 S.replace(old, new[, count]) -> str 4 子串替换 5 old：旧的子串 6 new：新的子串 7 count：替换的次数 8 Return a copy of S with all occurrences of substring 9 old replaced by new. If the optional argument count is 10 given, only the first count occurrences are replaced. 11 """ 12 return ""
>>> str = "1234561231"
>>> str.replace("1","a")
'a23456a23a'
>>> str.replace("1","a",1)
'a234561231'
17.split（分隔字符串，从左侧开始), splitlines（以换行符为分隔符分隔字符串）
1 def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__ 2 """ 3 S.split(sep=None, maxsplit=-1) -> list of strings 4 分隔字符串 5 sep：分隔符 6 maxsplit：最多分隔的次数 7 Return a list of the words in S, using sep as the 8 delimiter string. If maxsplit is given, at most maxsplit 9 splits are done. If sep is not specified or is None, any 10 whitespace string is a separator and empty strings are 11 removed from the result. 12 """ 13 return []
1 def splitlines(self, keepends=None): # real signature unknown; restored from __doc__ 2 """ 3 S.splitlines([keepends]) -> list of strings 4 以换行符为分隔符分隔字符串 5 keepends：是否保留换行符 6 Return a list of the lines in S, breaking at line boundaries. 7 Line breaks are not included in the resulting list unless keepends 8 is given and true. 9 """ 10 return []
>>> str = "Jason"
>>> str.split()
['Jason']
>>> str.split('a')
['J', 'son']
>>> str = "Jason
HaHa
Jack
"
>>> str.splitlines()
['Jason', 'HaHa', 'Jack']
18.zfill（右对齐，以字符0填充）
1 def zfill(self, width): # real signature unknown; restored from __doc__ 2 """ 3 S.zfill(width) -> str 4 右对齐，以字符0填充 5 width：宽度 6 Pad a numeric string S with zeros on the left, to fill a field 7 of the specified width. The string S is never truncated. 8 """ 9 return ""
>>> str = 'Python'
>>> str.zfill(10)
'0000Python'
五、列表
Python的列表是一种内置的数据类型，是由Python的基本数据类型组成的有序的集合。有点类似C语言的数组，但与数组不同的是，Python在定义列表的时候不用指定列表的容积（长度），可根据需要任意扩展，另外列表的内的元素可以是不同的数据类型，当然既然是任何数据类型，当然也包括另一个列表也就是嵌套。Python中列表使用中括号[]括起来，例如['Jack', 22, 'James', False, ['Jack', 22, 'James', False]].
1、列表的切片
通字符串一样列表也支持切片操作，例如我们有一个列表A_list = ['Michael', 'Bob', 'Tracy']
>>> A_list = ['Jack',22,'James',False]
>>> B_list = ['Jack',22,'James',False,A_list]
>>> print(B_list)
['Jack', 22, 'James', False, ['Jack', 22, 'James', False]]
如：[11,22,33]、['Jason', 'James']
每个列表都具备如下功能：
class list(object): """ list() -> new empty list list(iterable) -> new list initialized from iterable's items """ def append(self, p_object): # real signature unknown; restored from __doc__ """ L.append(object) -- append object to end """ pass def count(self, value): # real signature unknown; restored from __doc__ """ L.count(value) -> integer -- return number of occurrences of value """ return 0 def extend(self, iterable): # real signature unknown; restored from __doc__ """ L.extend(iterable) -- extend list by appending elements from the iterable """ pass def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ """ L.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present. """ return 0 def insert(self, index, p_object): # real signature unknown; restored from __doc__ """ L.insert(index, object) -- insert object before index """ pass def pop(self, index=None): # real signature unknown; restored from __doc__ """ L.pop([index]) -> item -- remove and return item at index (default last). Raises IndexError if list is empty or index is out of range. """ pass def remove(self, value): # real signature unknown; restored from __doc__ """ L.remove(value) -- remove first occurrence of value. Raises ValueError if the value is not present. """ pass def reverse(self): # real signature unknown; restored from __doc__ """ L.reverse() -- reverse *IN PLACE* """ pass def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__ """ L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*; cmp(x, y) -> -1, 0, 1 """ pass def __add__(self, y): # real signature unknown; restored from __doc__ """ x.__add__(y) <==> x+y """ pass def __contains__(self, y): # real signature unknown; restored from __doc__ """ x.__contains__(y) <==> y in x """ pass def __delitem__(self, y): # real signature unknown; restored from __doc__ """ x.__delitem__(y) <==> del x[y] """ pass def __delslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__delslice__(i, j) <==> del x[i:j] Use of negative indices is not supported. """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported. """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __iadd__(self, y): # real signature unknown; restored from __doc__ """ x.__iadd__(y) <==> x+=y """ pass def __imul__(self, y): # real signature unknown; restored from __doc__ """ x.__imul__(y) <==> x*=y """ pass def __init__(self, seq=()): # known special case of list.__init__ """ list() -> new empty list list(iterable) -> new list initialized from iterable's items # (copied from class doc) """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass def __mul__(self, n): # real signature unknown; restored from __doc__ """ x.__mul__(n) <==> x*n """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __reversed__(self): # real signature unknown; restored from __doc__ """ L.__reversed__() -- return a reverse iterator over the list """ pass def __rmul__(self, n): # real signature unknown; restored from __doc__ """ x.__rmul__(n) <==> n*x """ pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__ """ x.__setitem__(i, y) <==> x[i]=y """ pass def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__ """ x.__setslice__(i, j, y) <==> x[i:j]=y Use of negative indices is not supported. """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ L.__sizeof__() -- size of L in memory, in bytes """ pass __hash__ = None list
1）列表中索引号为n的元素（一样是从0开始计数哦）
>>> A_list[1]
22
2）从第m个元素到第n个元素
>>> A_list[0:2]
['Jack', 22]
3）从第m个元素到第n个元素，步长为p（也就是每隔p-1个字符）
>>> A_list[0:3:2]
['Jack', 'James']
说明：同字符串一样，列表的切片同样省略索引号和支持复数，用法与字符串一样，这里就不复述了。
2、列表的内置方法
Python中查看一个对象的内置方法和属性可以使用内置的dir方法，比如我们查看列表A_list的方法和属性
>>> dir(A_list) ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
>>> A_list = ['Jack',22,'James',False]
>>> A_list.append('Jason')# 在末尾插入一个新的元素
>>> A_list
['Jack', 22, 'James', False, 'Jason']
>>> A_list.index(1,'Michael')# 在指定位置（索引号）插入一个新的元素
>>> A_list
['Jack', 'Michael', 22, 'James', False, 'Jason']
>>> A_list.pop()#删除最后一个元素，并返回该元素，如果列表已经为空在执行pop方法会报错，类似IndexError: pop from empty list
'Jason'
>>> A_list
['Jack', 'Michael', 22, 'James', False]
>>> A_list.remove('Jack')# 删除指定的元素，注意这里接受的参数是元素，而不是索引号，如果元素不存在则报错，类似ValueError:
>>> A_list
['Michael', 22, 'James', False]
>>> A_list.remove('Jack')
Traceback (most recent call last):
File "<input>", line 1, in <module>
ValueError: list.remove(x): x not in list
>>> A_list.index('James')# 返回指定元素所在位置的索引号，如果元素不存在则报错ValueError: 'dafda' is not in list
2
>>> A_list.sort()
Traceback (most recent call last):
File "<input>", line 1, in <module>
TypeError: unorderable types: int() < str()
>>> A_list
['Michael', 22, 'James', False]
>>> A_list.remove(22)
>>> A_list
['Michael', 'James', False]
>>> A_list.sort()
Traceback (most recent call last):
File "<input>", line 1, in <module>
TypeError: unorderable types: bool() < str()
>>> A_list.remove(False)
>>> A_list.sort()#排序，注意Python3已经不支持不同类型数据的排序，如果列表内元素的类型不一致，就会报错，类似TypeError: unorderable types: str() < list()
>>> A_list
['James', 'Michael']
>>> A_list.reverse()# 翻转列表的元素位置
>>> A_list
['Michael', 'James']
>>> A_list.extend(B_list)# 将另一个列表的每一个元素追加到列表的末尾，注意与append不同，append会把另一列表当成一个元素追加到列表的末尾
>>> A_list
['Michael', 'James', 'Jack', 22, 'James', False, [...]]
>>> A_list.count('James')# 返回列表的某一个元素重复的个数，如果元素不存在返回0，不会报错
2
我们上面说index方法和remove方法只能返回或删除第一查找到的元素，如果一个列表中重复出现多次我们如何处理呢，这时候我们可以这么处理
全部删除：原理就是先求出出现了多少次，然后通过循环删除
1 #!/usr/bin/env python 2 # coding:utf-8 3 name_list = ['Michael', 'Jack', 'Bob', 'Tracy', 'Peter', 'Jack'] # 这里有两'Jack' 4 # 返回所有'Jack'的索引 5 for i in range(name_list.count('Jack')): 6 name_list.remove('Jack') 7 print(name_list)
查询所有的索引号，原理就是先求出一共出现了多少次，第一次直接查找返回说因，从第二次开始开始，从上一次的索引位置的下一个位置进行切片，然后再进行查，那么这一次的索引号就是上一次的索引号+加上本次的索引+1，依次类推
1 #!/usr/bin/env python 2 # coding:utf-8 3 name_list = ['Jack', 'Michael', 'Jack', 'Bob', 'Tracy', 'Peter', 'Jack'] # 这里有三个'Jack' 4 # 返回所有'Jack'的索引 5 index_num = 0 # 定义初始索引号 6 index_list = [] # 定义用来存储索引号的列表 7 for i in range(name_list.count('Jack')): 8 if i != 0: # i不等于0也就是说不是第一次查找 9 index_num = name_list[index_num+1:].index('Jack') + index_num + 1 10 else: # 否则就是第一次查找，直接返回索引号即可 11 index_num = name_list.index('Jack') 12 index_list.append(index_num) # 将索引号追加到index_list中 13 print(index_list)
注：排序；
六、元组
如：(11,22,33)、('Jason', 'James')
每个元组都具备如下功能：
class tuple(object): """ tuple() -> empty tuple tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object. """ def count(self, value): # real signature unknown; restored from __doc__ """ T.count(value) -> integer -- return number of occurrences of value """ return 0 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ """ T.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present. """ return 0 def __add__(self, y): # real signature unknown; restored from __doc__ """ x.__add__(y) <==> x+y """ pass def __contains__(self, y): # real signature unknown; restored from __doc__ """ x.__contains__(y) <==> y in x """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __getnewargs__(self, *args, **kwargs): # real signature unknown pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported. """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __hash__(self): # real signature unknown; restored from __doc__ """ x.__hash__() <==> hash(x) """ pass def __init__(self, seq=()): # known special case of tuple.__init__ """ tuple() -> empty tuple tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object. # (copied from class doc) """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass def __mul__(self, n): # real signature unknown; restored from __doc__ """ x.__mul__(n) <==> x*n """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __rmul__(self, n): # real signature unknown; restored from __doc__ """ x.__rmul__(n) <==> n*x """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ T.__sizeof__() -- size of T in memory, in bytes """ pass tuple
元祖和列表非常类似，但是元祖一旦初始化就不能修改，所以元祖除了可以切片外没有列表的那些方法。
但是我们所说的元祖的不可变不是绝对的，也可以是“可变的”，那就是元祖里的元素是其他可变的数据类型，如列表等
例如：t = ('a', 'b', ['A', 'B'])
注意里面列表，我们要对这个列表进行一些修改操作：
>>> t = ('a', 'b', ['A', 'B'])
>>> t[2][0] = 'X'
>>> t
('a', 'b', ['X', 'B'])
>>> t[2].append('C')
>>> t
('a', 'b', ['X', 'B', 'C'])
可以看出如果元祖里有可变数据类型的元素，那么该元素是依然可以修改的，这使得元祖貌似被修改了，其实并没有修改，因为Python一切皆指针。
七、字典
一、字典简介
字典dict（dictionary），在其他语言中也成为map，使用键-值（key-value）的形式存储和展现，具有极快的查找速度。
字典的定义
d = {'key':value,...}
字典可以嵌套，value也可以使用列表等数据类型
字典通过键获取键所对应的值
d[key]
如：{'name': 'Jason', 'age': 18} 、{'host': '2.2.2.2', 'port': 80]}
1、clear（清除字典所有元素）
代码：
1 def clear(self): # real signature unknown; restored from __doc__ 2 """ D.clear() -> None. Remove all items from D. 3 清除所有元素 4 """ 5 pass
示例：
>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.clear()
>>> dic
{}
2、copy（浅拷贝）
代码：
1 def copy(self): # real signature unknown; restored from __doc__ 2 """ D.copy() -> a shallow copy of D 3 浅拷贝，返回的是一个新的字典对象 4 """ 5 pass
示例：
>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic2 = dic.copy()
>>> dic2
{'age': 25, 'name': 'Jason', 'address': 'beijing china'}
注意：拷贝和赋值dic2 = dic完全不一样，等到讲到深浅拷贝的时候再来探讨这个问题
3、fromkeys（创建新的字典对象）
代码：
1 @staticmethod # known case 2 def fromkeys(*args, **kwargs): # real signature unknown 3 """ Returns a new dict with keys from iterable and values equal to value. 4 用于创建一个新字典，以序列seq中元素做字典的键，value为字典所有键对应的初始值 5 """ 6 pass
示例：
>>> dic = dict.fromkeys(['name','age'],10)
>>> dic
{'age': 10, 'name': 10}
4、get（获取键所对应的值）
代码：
1 def get(self, k, d=None): # real signature unknown; restored from __doc__ 2 """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. 3 获取键所对应的值如果存在返回值，如果不存在返回d所定义的值 4 k：key 5 d：默认值，如果不存在返回的值 6 """ 7 pass
示例：
>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.get('name')
'Jason'
>>> dic.get('hobby','23')
'23'
>>> dic.get('hobby')
注意：与d[key]取值不同的是，get方法如果key不存在则返回默认值，如果没定义返回的是None，而d[key]这种方式key不存在则会报错
>>> dic['hobby']
Traceback (most recent call last):
File "<input>", line 1, in <module>
KeyError: 'hobby'
5、items（返回键值组成的元祖）
代码：
1 def items(self): # real signature unknown; restored from __doc__ 2 """ D.items() -> a set-like object providing a view on D's items 3 返回键值组成的元祖列表，也就是同时返回键和值 4 """ 5 pass
示例：
>>> dic.items()
dict_items([('age', 25), ('name', 'Jason'), ('address', 'beijing china')])
6、keys（返回字典的key）
代码：
1 def keys(self): # real signature unknown; restored from __doc__ 2 """ D.keys() -> a set-like object providing a view on D's keys 3 返回字典的所有的key 4 """ 5 pass
示例：
>>> dic.keys()
dict_keys(['age', 'name', 'address'])
说明：2.X返回的直接是列表对象，3.X返回的dict_keys对象，但是也能通过in做是否存在的判断或循环
7、pop（删除指定key的元素，并返回key所对应的值）
代码：
1 def pop(self, k, d=None): # real signature unknown; restored from __doc__ 2 """ 3 D.pop(k[,d]) -> v, remove specified key and return the corresponding value. 4 If key is not found, d is returned if given, otherwise KeyError is raised 5 删除指定key的元素，并返回key所对应的值，如果不存在返回默认值 6 k：key 7 d：默认值，如果不存在返回的值 8 """ 9 pass
示例：
>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china'}
>>> dic.pop('name')
'Jason'
>>> dic
{'age': 25, 'address': 'beijing china'}
>>> dic.pop('hobby','123')
'123'
8、popitem（删除元素）
代码
1 def popitem(self): # real signature unknown; restored from __doc__ 2 """ 3 D.popitem() -> (k, v), remove and return some (key, value) pair as a 4 2-tuple; but raise KeyError if D is empty. 5 删除元素并返回删除的元素key和value组成的元祖 6 """ 7 pass
示例：
>>> dic = {'name':'zhangxiaoyu', 'age':35, 'address':'beijing china'}
>>> dic.popitem()
('age', 35)
>>> dic
{'address': 'beijing china', 'name': 'zhangxiaoyu'}
注意：由于字典是无序的，所以使用这个方法删除的不一定是哪个元素，所以慎用
9、setdefault（设置默认值，这个方法要与get方法配合使用相当于get方法的d参数）
代码：
1 def setdefault(self, k, d=None): # real signature unknown; restored from __doc__ 2 """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D 3 设置默认值，这个方法要与get方法配合使用相当于get方法的d参数，同样也适用于d[key]这种取值方法 4 5 """ 6 pass
示例：
>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.setdefault('hobby',"basketball")
'basketball'
>>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china', 'hobby': 'basketball'}
感觉完全是设置了一个新的键值对
10、update（将另一个字典的键值添加到当前字典中）
代码：
1 def update(self, E=None, **F): # known special case of dict.update 2 """ 3 D.update([E, ]**F) -> None. Update D from dict/iterable E and F. 4 If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] 5 If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v 6 In either case, this is followed by: for k in F: D[k] = F[k] 7 将另一个字典的键值添加到当前字典中 8 不存在的键直接添加，存在的键将被覆盖 9 """ 10 pass
示例：
>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china', 'hobby': 'basketball'}
>>> dic2 = {'gender':'male','name':'luis'}
>>> dic.update(dic2)
>>> dic
{'age': 25, 'address': 'beijing china', 'gender': 'male', 'hobby': 'basketball', 'name': 'luis'}
11、values（返回所有的值）
代码：
1 def values(self): # real signature unknown; restored from __doc__ 2 """ D.values() -> an object providing a view on D's values 3 返回字典所有的值 4 """ 5 pass
示例：
>>> dic.values()
dict_values([25, 'beijing china', 'male', 'basketball', 'luis'])
ps：循环时，默认循环key
每个字典都具备如下功能：
1 class dict(object): 2 """ 3 dict() -> new empty dictionary 4 dict(mapping) -> new dictionary initialized from a mapping object's 5 (key, value) pairs 6 dict(iterable) -> new dictionary initialized as if via: 7 d = {} 8 for k, v in iterable: 9 d[k] = v 10 dict(**kwargs) -> new dictionary initialized with the name=value pairs 11 in the keyword argument list. For example: dict(one=1, two=2) 12 """ 13 14 def clear(self): # real signature unknown; restored from __doc__ 15 """ 清除内容 """ 16 """ D.clear() -> None. Remove all items from D. """ 17 pass 18 19 def copy(self): # real signature unknown; restored from __doc__ 20 """ 浅拷贝 """ 21 """ D.copy() -> a shallow copy of D """ 22 pass 23 24 @staticmethod # known case 25 def fromkeys(S, v=None): # real signature unknown; restored from __doc__ 26 """ 27 dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v. 28 v defaults to None. 29 """ 30 pass 31 32 def get(self, k, d=None): # real signature unknown; restored from __doc__ 33 """ 根据key获取值，d是默认值 """ 34 """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """ 35 pass 36 37 def has_key(self, k): # real signature unknown; restored from __doc__ 38 """ 是否有key """ 39 """ D.has_key(k) -> True if D has a key k, else False """ 40 return False 41 42 def items(self): # real signature unknown; restored from __doc__ 43 """ 所有项的列表形式 """ 44 """ D.items() -> list of D's (key, value) pairs, as 2-tuples """ 45 return [] 46 47 def iteritems(self): # real signature unknown; restored from __doc__ 48 """ 项可迭代 """ 49 """ D.iteritems() -> an iterator over the (key, value) items of D """ 50 pass 51 52 def iterkeys(self): # real signature unknown; restored from __doc__ 53 """ key可迭代 """ 54 """ D.iterkeys() -> an iterator over the keys of D """ 55 pass 56 57 def itervalues(self): # real signature unknown; restored from __doc__ 58 """ value可迭代 """ 59 """ D.itervalues() -> an iterator over the values of D """ 60 pass 61 62 def keys(self): # real signature unknown; restored from __doc__ 63 """ 所有的key列表 """ 64 """ D.keys() -> list of D's keys """ 65 return [] 66 67 def pop(self, k, d=None): # real signature unknown; restored from __doc__ 68 """ 获取并在字典中移除 """ 69 """ 70 D.pop(k[,d]) -> v, remove specified key and return the corresponding value. 71 If key is not found, d is returned if given, otherwise KeyError is raised 72 """ 73 pass 74 75 def popitem(self): # real signature unknown; restored from __doc__ 76 """ 获取并在字典中移除 """ 77 """ 78 D.popitem() -> (k, v), remove and return some (key, value) pair as a 79 2-tuple; but raise KeyError if D is empty. 80 """ 81 pass 82 83 def setdefault(self, k, d=None): # real signature unknown; restored from __doc__ 84 """ 如果key不存在，则创建，如果存在，则返回已存在的值且不修改 """ 85 """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """ 86 pass 87 88 def update(self, E=None, **F): # known special case of dict.update 89 """ 更新 90 {'name':'alex', 'age': 18000} 91 [('name','sbsbsb'),] 92 """ 93 """ 94 D.update([E, ]**F) -> None. Update D from dict/iterable E and F. 95 If E present and has a .keys() method, does: for k in E: D[k] = E[k] 96 If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v 97 In either case, this is followed by: for k in F: D[k] = F[k] 98 """ 99 pass 100 101 def values(self): # real signature unknown; restored from __doc__ 102 """ 所有的值 """ 103 """ D.values() -> list of D's values """ 104 return [] 105 106 def viewitems(self): # real signature unknown; restored from __doc__ 107 """ 所有项，只是将内容保存至view对象中 """ 108 """ D.viewitems() -> a set-like object providing a view on D's items """ 109 pass 110 111 def viewkeys(self): # real signature unknown; restored from __doc__ 112 """ D.viewkeys() -> a set-like object providing a view on D's keys """ 113 pass 114 115 def viewvalues(self): # real signature unknown; restored from __doc__ 116 """ D.viewvalues() -> an object providing a view on D's values """ 117 pass 118 119 def __cmp__(self, y): # real signature unknown; restored from __doc__ 120 """ x.__cmp__(y) <==> cmp(x,y) """ 121 pass 122 123 def __contains__(self, k): # real signature unknown; restored from __doc__ 124 """ D.__contains__(k) -> True if D has a key k, else False """ 125 return False 126 127 def __delitem__(self, y): # real signature unknown; restored from __doc__ 128 """ x.__delitem__(y) <==> del x[y] """ 129 pass 130 131 def __eq__(self, y): # real signature unknown; restored from __doc__ 132 """ x.__eq__(y) <==> x==y """ 133 pass 134 135 def __getattribute__(self, name): # real signature unknown; restored from __doc__ 136 """ x.__getattribute__('name') <==> x.name """ 137 pass 138 139 def __getitem__(self, y): # real signature unknown; restored from __doc__ 140 """ x.__getitem__(y) <==> x[y] """ 141 pass 142 143 def __ge__(self, y): # real signature unknown; restored from __doc__ 144 """ x.__ge__(y) <==> x>=y """ 145 pass 146 147 def __gt__(self, y): # real signature unknown; restored from __doc__ 148 """ x.__gt__(y) <==> x>y """ 149 pass 150 151 def __init__(self, seq=None, **kwargs): # known special case of dict.__init__ 152 """ 153 dict() -> new empty dictionary 154 dict(mapping) -> new dictionary initialized from a mapping object's 155 (key, value) pairs 156 dict(iterable) -> new dictionary initialized as if via: 157 d = {} 158 for k, v in iterable: 159 d[k] = v 160 dict(**kwargs) -> new dictionary initialized with the name=value pairs 161 in the keyword argument list. For example: dict(one=1, two=2) 162 # (copied from class doc) 163 """ 164 pass 165 166 def __iter__(self): # real signature unknown; restored from __doc__ 167 """ x.__iter__() <==> iter(x) """ 168 pass 169 170 def __len__(self): # real signature unknown; restored from __doc__ 171 """ x.__len__() <==> len(x) """ 172 pass 173 174 def __le__(self, y): # real signature unknown; restored from __doc__ 175 """ x.__le__(y) <==> x<=y """ 176 pass 177 178 def __lt__(self, y): # real signature unknown; restored from __doc__ 179 """ x.__lt__(y) <==> x<y """ 180 pass 181 182 @staticmethod # known case of __new__ 183 def __new__(S, *more): # real signature unknown; restored from __doc__ 184 """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ 185 pass 186 187 def __ne__(self, y): # real signature unknown; restored from __doc__ 188 """ x.__ne__(y) <==> x!=y """ 189 pass 190 191 def __repr__(self): # real signature unknown; restored from __doc__ 192 """ x.__repr__() <==> repr(x) """ 193 pass 194 195 def __setitem__(self, i, y): # real signature unknown; restored from __doc__ 196 """ x.__setitem__(i, y) <==> x[i]=y """ 197 pass 198 199 def __sizeof__(self): # real signature unknown; restored from __doc__ 200 """ D.__sizeof__() -> size of D in memory, in bytes """ 201 pass 202 203 __hash__ = None 204 205 dict
练习：元素分类
有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。
即： {'k1': 大于66 , 'k2': 小于66}
八、set集合
set是一个无序且不重复的元素集合
class set(object): """ set() -> new empty set object set(iterable) -> new set object Build an unordered collection of unique elements. """ def add(self, *args, **kwargs): # real signature unknown """ 添加 """ """ Add an element to a set. This has no effect if the element is already present. """ pass def clear(self, *args, **kwargs): # real signature unknown """ Remove all elements from this set. """ pass def copy(self, *args, **kwargs): # real signature unknown """ Return a shallow copy of a set. """ pass def difference(self, *args, **kwargs): # real signature unknown """ Return the difference of two or more sets as a new set. (i.e. all elements that are in this set but not the others.) """ pass def difference_update(self, *args, **kwargs): # real signature unknown """ 删除当前set中的所有包含在 new set 里的元素 """ """ Remove all elements of another set from this set. """ pass def discard(self, *args, **kwargs): # real signature unknown """ 移除元素 """ """ Remove an element from a set if it is a member. If the element is not a member, do nothing. """ pass def intersection(self, *args, **kwargs): # real signature unknown """ 取交集，新创建一个set """ """ Return the intersection of two or more sets as a new set. (i.e. elements that are common to all of the sets.) """ pass def intersection_update(self, *args, **kwargs): # real signature unknown """ 取交集，修改原来set """ """ Update a set with the intersection of itself and another. """ pass def isdisjoint(self, *args, **kwargs): # real signature unknown """ 如果没有交集，返回true """ """ Return True if two sets have a null intersection. """ pass def issubset(self, *args, **kwargs): # real signature unknown """ 是否是子集 """ """ Report whether another set contains this set. """ pass def issuperset(self, *args, **kwargs): # real signature unknown """ 是否是父集 """ """ Report whether this set contains another set. """ pass def pop(self, *args, **kwargs): # real signature unknown """ 移除 """ """ Remove and return an arbitrary set element. Raises KeyError if the set is empty. """ pass def remove(self, *args, **kwargs): # real signature unknown """ 移除 """ """ Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError. """ pass def symmetric_difference(self, *args, **kwargs): # real signature unknown """ 差集，创建新对象""" """ Return the symmetric difference of two sets as a new set. (i.e. all elements that are in exactly one of the sets.) """ pass def symmetric_difference_update(self, *args, **kwargs): # real signature unknown """ 差集，改变原来 """ """ Update a set with the symmetric difference of itself and another. """ pass def union(self, *args, **kwargs): # real signature unknown """ 并集 """ """ Return the union of sets as a new set. (i.e. all elements that are in either set.) """ pass def update(self, *args, **kwargs): # real signature unknown """ 更新 """ """ Update a set with the union of itself and others. """ pass def __and__(self, y): # real signature unknown; restored from __doc__ """ x.__and__(y) <==> x&y """ pass def __cmp__(self, y): # real signature unknown; restored from __doc__ """ x.__cmp__(y) <==> cmp(x,y) """ pass def __contains__(self, y): # real signature unknown; restored from __doc__ """ x.__contains__(y) <==> y in x. """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __iand__(self, y): # real signature unknown; restored from __doc__ """ x.__iand__(y) <==> x&=y """ pass def __init__(self, seq=()): # known special case of set.__init__ """ set() -> new empty set object set(iterable) -> new set object Build an unordered collection of unique elements. # (copied from class doc) """ pass def __ior__(self, y): # real signature unknown; restored from __doc__ """ x.__ior__(y) <==> x|=y """ pass def __isub__(self, y): # real signature unknown; restored from __doc__ """ x.__isub__(y) <==> x-=y """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __ixor__(self, y): # real signature unknown; restored from __doc__ """ x.__ixor__(y) <==> x^=y """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __or__(self, y): # real signature unknown; restored from __doc__ """ x.__or__(y) <==> x|y """ pass def __rand__(self, y): # real signature unknown; restored from __doc__ """ x.__rand__(y) <==> y&x """ pass def __reduce__(self, *args, **kwargs): # real signature unknown """ Return state information for pickling. """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __ror__(self, y): # real signature unknown; restored from __doc__ """ x.__ror__(y) <==> y|x """ pass def __rsub__(self, y): # real signature unknown; restored from __doc__ """ x.__rsub__(y) <==> y-x """ pass def __rxor__(self, y): # real signature unknown; restored from __doc__ """ x.__rxor__(y) <==> y^x """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ S.__sizeof__() -> size of S in memory, in bytes """ pass def __sub__(self, y): # real signature unknown; restored from __doc__ """ x.__sub__(y) <==> x-y """ pass def __xor__(self, y): # real signature unknown; restored from __doc__ """ x.__xor__(y) <==> x^y """ pass __hash__ = None set
>>> old_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
}
>>> new_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 },
}
>>> a=set(old_dict)
>>> b=set(new_dict)
>>> a.difference(b)
{'#2'}
>>> a.intersection(b)
{'#1', '#3'}
>>> a.symmetric_difference(b)
{'#4', '#2'}
if __name__ == '__main__': old_dict = { "#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }, "#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }, "#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 } } new_dict = { "#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 }, "#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }, "#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 } } s1 = set(old_dict) s2 = set(new_dict) new_list = [] new_set = s1.difference(s2) for new_item in new_set: new_list.append(old_dict[new_item]) print(new_list) print(new_set) print(s1)
##set update conf output
[{'hostname': 'c1', 'mem_capicity': 80, 'cpu_count': 2}]
{'#2'}
{'#3', '#2', '#1'}
练习：寻找差异 # 数据库中原有 old_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }, "#2":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } } # cmdb 新汇报的数据 new_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 800 }, "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#4":{ 'hostname':c2, 'cpu_count': 2, 'mem_capicity': 80 } } 需要删除：？ 需要新建：？ 需要更新：？ 注意：无需考虑内部元素是否改变，只要原来存在，新汇报也存在，就是需要更新
练习：寻找差异 # 数据库中原有 old_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }, "#2":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } } # cmdb 新汇报的数据 new_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 800 }, "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#4":{ 'hostname':c2, 'cpu_count': 2, 'mem_capicity': 80 } } 需要删除：？ 需要新建：？ 需要更新：？ 注意：无需考虑内部元素是否改变，只要原来存在，新汇报也存在，就是需要更新
九.深浅拷贝（）
# 浅拷贝
# copy.copy()
# 深拷贝
# copy.deepcopy()
# 赋值
# =
# 数字和字符串的浅拷贝、深拷贝、和赋值都是引用的相同的内存地址
1 """Generic (shallow and deep) copying operations. 2 3 Interface summary: 4 5 import copy 6 7 x = copy.copy(y) # make a shallow copy of y 8 x = copy.deepcopy(y) # make a deep copy of y 9 10 For module specific errors, copy.Error is raised. 11 12 The difference between shallow and deep copying is only relevant for 13 compound objects (objects that contain other objects, like lists or 14 class instances). 15 16 - A shallow copy constructs a new compound object and then (to the 17 extent possible) inserts *the same objects* into it that the 18 original contains. 19 20 - A deep copy constructs a new compound object and then, recursively, 21 inserts *copies* into it of the objects found in the original. 22 23 Two problems often exist with deep copy operations that don't exist 24 with shallow copy operations: 25 26 a) recursive objects (compound objects that, directly or indirectly, 27 contain a reference to themselves) may cause a recursive loop 28 29 b) because deep copy copies *everything* it may copy too much, e.g. 30 administrative data structures that should be shared even between 31 copies 32 33 Python's deep copy operation avoids these problems by: 34 35 a) keeping a table of objects already copied during the current 36 copying pass 37 38 b) letting user-defined classes override the copying operation or the 39 set of components copied 40 41 This version does not copy types like module, class, function, method, 42 nor stack trace, stack frame, nor file, socket, window, nor array, nor 43 any similar types. 44 45 Classes can use the same interfaces to control copying that they use 46 to control pickling: they can define methods called __getinitargs__(), 47 __getstate__() and __setstate__(). See the documentation for module 48 "pickle" for information on these methods. 49 """ 50 51 import types 52 import weakref 53 from copyreg import dispatch_table 54 import builtins 55 56 class Error(Exception): 57 pass 58 error = Error # backward compatibility 59 60 try: 61 from org.python.core import PyStringMap 62 except ImportError: 63 PyStringMap = None 64 65 __all__ = ["Error", "copy", "deepcopy"] 66 67 def copy(x): 68 """Shallow copy operation on arbitrary Python objects. 69 70 See the module's __doc__ string for more info. 71 """ 72 73 cls = type(x) 74 75 copier = _copy_dispatch.get(cls) 76 if copier: 77 return copier(x) 78 79 try: 80 issc = issubclass(cls, type) 81 except TypeError: # cls is not a class 82 issc = False 83 if issc: 84 # treat it as a regular class: 85 return _copy_immutable(x) 86 87 copier = getattr(cls, "__copy__", None) 88 if copier: 89 return copier(x) 90 91 reductor = dispatch_table.get(cls) 92 if reductor: 93 rv = reductor(x) 94 else: 95 reductor = getattr(x, "__reduce_ex__", None) 96 if reductor: 97 rv = reductor(4) 98 else: 99 reductor = getattr(x, "__reduce__", None) 100 if reductor: 101 rv = reductor() 102 else: 103 raise Error("un(shallow)copyable object of type %s" % cls) 104 105 return _reconstruct(x, rv, 0) 106 107 108 _copy_dispatch = d = {} 109 110 def _copy_immutable(x): 111 return x 112 for t in (type(None), int, float, bool, str, tuple, 113 bytes, frozenset, type, range, 114 types.BuiltinFunctionType, type(Ellipsis), 115 types.FunctionType, weakref.ref): 116 d[t] = _copy_immutable 117 t = getattr(types, "CodeType", None) 118 if t is not None: 119 d[t] = _copy_immutable 120 for name in ("complex", "unicode"): 121 t = getattr(builtins, name, None) 122 if t is not None: 123 d[t] = _copy_immutable 124 125 def _copy_with_constructor(x): 126 return type(x)(x) 127 for t in (list, dict, set): 128 d[t] = _copy_with_constructor 129 130 def _copy_with_copy_method(x): 131 return x.copy() 132 if PyStringMap is not None: 133 d[PyStringMap] = _copy_with_copy_method 134 135 del d 136 137 def deepcopy(x, memo=None, _nil=[]): 138 """Deep copy operation on arbitrary Python objects. 139 140 See the module's __doc__ string for more info. 141 """ 142 143 if memo is None: 144 memo = {} 145 146 d = id(x) 147 y = memo.get(d, _nil) 148 if y is not _nil: 149 return y 150 151 cls = type(x) 152 153 copier = _deepcopy_dispatch.get(cls) 154 if copier: 155 y = copier(x, memo) 156 else: 157 try: 158 issc = issubclass(cls, type) 159 except TypeError: # cls is not a class (old Boost; see SF #502085) 160 issc = 0 161 if issc: 162 y = _deepcopy_atomic(x, memo) 163 else: 164 copier = getattr(x, "__deepcopy__", None) 165 if copier: 166 y = copier(memo) 167 else: 168 reductor = dispatch_table.get(cls) 169 if reductor: 170 rv = reductor(x) 171 else: 172 reductor = getattr(x, "__reduce_ex__", None) 173 if reductor: 174 rv = reductor(4) 175 else: 176 reductor = getattr(x, "__reduce__", None) 177 if reductor: 178 rv = reductor() 179 else: 180 raise Error( 181 "un(deep)copyable object of type %s" % cls) 182 y = _reconstruct(x, rv, 1, memo) 183 184 # If is its own copy, don't memoize. 185 if y is not x: 186 memo[d] = y 187 _keep_alive(x, memo) # Make sure x lives at least as long as d 188 return y 189 190 _deepcopy_dispatch = d = {} 191 192 def _deepcopy_atomic(x, memo): 193 return x 194 d[type(None)] = _deepcopy_atomic 195 d[type(Ellipsis)] = _deepcopy_atomic 196 d[int] = _deepcopy_atomic 197 d[float] = _deepcopy_atomic 198 d[bool] = _deepcopy_atomic 199 try: 200 d[complex] = _deepcopy_atomic 201 except NameError: 202 pass 203 d[bytes] = _deepcopy_atomic 204 d[str] = _deepcopy_atomic 205 try: 206 d[types.CodeType] = _deepcopy_atomic 207 except AttributeError: 208 pass 209 d[type] = _deepcopy_atomic 210 d[range] = _deepcopy_atomic 211 d[types.BuiltinFunctionType] = _deepcopy_atomic 212 d[types.FunctionType] = _deepcopy_atomic 213 d[weakref.ref] = _deepcopy_atomic 214 215 def _deepcopy_list(x, memo): 216 y = [] 217 memo[id(x)] = y 218 for a in x: 219 y.append(deepcopy(a, memo)) 220 return y 221 d[list] = _deepcopy_list 222 223 def _deepcopy_tuple(x, memo): 224 y = [deepcopy(a, memo) for a in x] 225 # We're not going to put the tuple in the memo, but it's still important we 226 # check for it, in case the tuple contains recursive mutable structures. 227 try: 228 return memo[id(x)] 229 except KeyError: 230 pass 231 for k, j in zip(x, y): 232 if k is not j: 233 y = tuple(y) 234 break 235 else: 236 y = x 237 return y 238 d[tuple] = _deepcopy_tuple 239 240 def _deepcopy_dict(x, memo): 241 y = {} 242 memo[id(x)] = y 243 for key, value in x.items(): 244 y[deepcopy(key, memo)] = deepcopy(value, memo) 245 return y 246 d[dict] = _deepcopy_dict 247 if PyStringMap is not None: 248 d[PyStringMap] = _deepcopy_dict 249 250 def _deepcopy_method(x, memo): # Copy instance methods 251 return type(x)(x.__func__, deepcopy(x.__self__, memo)) 252 _deepcopy_dispatch[types.MethodType] = _deepcopy_method 253 254 def _keep_alive(x, memo): 255 """Keeps a reference to the object x in the memo. 256 257 Because we remember objects by their id, we have 258 to assure that possibly temporary objects are kept 259 alive by referencing them. 260 We store a reference at the id of the memo, which should 261 normally not be used unless someone tries to deepcopy 262 the memo itself... 263 """ 264 try: 265 memo[id(memo)].append(x) 266 except KeyError: 267 # aha, this is the first one :-) 268 memo[id(memo)]=[x] 269 270 def _reconstruct(x, info, deep, memo=None): 271 if isinstance(info, str): 272 return x 273 assert isinstance(info, tuple) 274 if memo is None: 275 memo = {} 276 n = len(info) 277 assert n in (2, 3, 4, 5) 278 callable, args = info[:2] 279 if n > 2: 280 state = info[2] 281 else: 282 state = {} 283 if n > 3: 284 listiter = info[3] 285 else: 286 listiter = None 287 if n > 4: 288 dictiter = info[4] 289 else: 290 dictiter = None 291 if deep: 292 args = deepcopy(args, memo) 293 y = callable(*args) 294 memo[id(x)] = y 295 296 if state: 297 if deep: 298 state = deepcopy(state, memo) 299 if hasattr(y, '__setstate__'): 300 y.__setstate__(state) 301 else: 302 if isinstance(state, tuple) and len(state) == 2: 303 state, slotstate = state 304 else: 305 slotstate = None 306 if state is not None: 307 y.__dict__.update(state) 308 if slotstate is not None: 309 for key, value in slotstate.items(): 310 setattr(y, key, value) 311 312 if listiter is not None: 313 for item in listiter: 314 if deep: 315 item = deepcopy(item, memo) 316 y.append(item) 317 if dictiter is not None: 318 for key, value in dictiter: 319 if deep: 320 key = deepcopy(key, memo) 321 value = deepcopy(value, memo) 322 y[key] = value 323 return y 324 325 del d 326 327 del types 328 329 # Helper for instance creation without calling __init__ 330 class _EmptyClass: 331 pass
1 #!/usr/bin/env python 2 # -*-coding:utf-8-*- 3 # Author: Jason Wang 4 if __name__ == '__main__': 5 import copy 6 # 浅拷贝 7 # copy.copy() 8 # 深拷贝 9 # copy.deepcopy() 10 # 赋值 11 # = 12 # 数字和字符串的浅拷贝、深拷贝、和赋值都是引用的相同的内存地址 13 a1 = 123123 14 a2 = 123123 15 print("id a1:",id(a1)) 16 print("id a2:",id(a2)) 17 18 a1 = 234234 19 a2 = a1 20 print("id a1:",id(a1)) 21 print("id a2:",id(a2)) 22 23 a3 = copy.copy(a1) 24 print("id a3:",id(a3)) 25 26 a4 = copy.deepcopy(a1) 27 print("id a4:",id(a4)) 28 29 n1 = {"k1":"abc", "k2":123, "k3":["abc", 123]} 30 n2 = n1 31 print("id n1:",id(n1)) 32 print("id n2:",id(n2)) 33 n3 = copy.copy(n1) 34 print("id n3:",id(n3)) 35 n4 = copy.deepcopy(n1) 36 print("id n4:",id(n4)) 37 print("id n1['k3']:",id(n1['k3'])) 38 print("id n2['k3']:",id(n2['k3'])) 39 print("id n3['k3']:",id(n3['k3'])) 40 print("id n4['k3']:",id(n4['k3'])) 41 42 43 n3['k3'][0] = 'def' 44 print("n1['k3']",n1['k3']) 45 print("n2['k3']",n2['k3']) 46 print("n3['k3']",n3['k3']) 47 print("n4['k3']",n4['k3']) 48 49 50 dic = { 51 "cpu":[80], 52 53 }
##copy test output
id a1: 4330261904
id a2: 4330261904
id a1: 4329590608
id a2: 4329590608
id a3: 4329590608
id a4: 4329590608
id n1: 4330219144
id n2: 4330219144
id n3: 4332198600
id n4: 4332196616
id n1['k3']: 4332626760
id n2['k3']: 4332626760
id n3['k3']: 4332626760
id n4['k3']: 4332592968
n1['k3'] ['def', 123]
n2['k3'] ['def', 123]
n3['k3'] ['def', 123]
n4['k3'] ['abc', 123]
import json
li = [11,22,33]
json.dump(li,open('db','w'))#序列化
li = json.load(open('db','r'))##将字符产反序列化，读文件
print(type(li),li)
#<class 'list'> [11, 22, 33]