数字数据类型
Python 数字数据类型用于存储数值。
数据类型是不允许改变的,这就意味着如果改变数字数据类型得值，将重新分配内存空间。
支持四种不同的数值类型：
- int(整型)：整型或整数，是正或负整数，不带小数点。
- long integers(长整型)：无限大小的整数，整数最后是一个大写或小写的L。
- floating point real values(长整型)：浮点型由整数部分与小数部分组成，浮点型也可以使用科学计数法表示（2.5e2 = 2.5 x 102 = 250）
- complex numbers（复数）：复数由实数部分和虚数部分构成，可以用a + bj,或者complex(a,b)表示， 复数的实部a和虚部b都是浮点型。
1 #!/usr/bin/env python3 2 3 class int(object): 4 """ 5 int(x=0) -> integer 6 int(x, base=10) -> integer 7 8 Convert a number or string to an integer, or return 0 if no arguments 9 are given. If x is a number, return x.__int__(). For floating point 10 numbers, this truncates towards zero. 11 12 If x is not a number or if base is given, then x must be a string, 13 bytes, or bytearray instance representing an integer literal in the 14 given base. The literal can be preceded by '+' or '-' and be surrounded 15 by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. 16 Base 0 means to interpret the base from the string as an integer literal. 17 >>> int('0b100', base=0) 18 4 19 """ 20 def bit_length(self): # real signature unknown; restored from __doc__ 21 """ 22 '''返回表示该数字的时占用的最少位数''' 23 int.bit_length() -> int 24 25 Number of bits necessary to represent self in binary. 26 >>> bin(37) 27 '0b100101' 28 >>> (37).bit_length() 29 6 30 """ 31 return 0 32 33 def conjugate(self, *args, **kwargs): # real signature unknown 34 '''返回该复数的共轭复数''' 35 """ Returns self, the complex conjugate of any int. """ 36 pass 37 38 @classmethod # known case 39 def from_bytes(cls, bytes, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__ 40 """ 41 int.from_bytes(bytes, byteorder, *, signed=False) -> int 42 43 Return the integer represented by the given array of bytes. 44 45 The bytes argument must be a bytes-like object (e.g. bytes or bytearray). 46 47 The byteorder argument determines the byte order used to represent the 48 integer. If byteorder is 'big', the most significant byte is at the 49 beginning of the byte array. If byteorder is 'little', the most 50 significant byte is at the end of the byte array. To request the native 51 byte order of the host system, use `sys.byteorder' as the byte order value. 52 53 The signed keyword-only argument indicates whether two's complement is 54 used to represent the integer. 55 """ 56 pass 57 58 def to_bytes(self, length, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__ 59 """ 60 int.to_bytes(length, byteorder, *, signed=False) -> bytes 61 62 Return an array of bytes representing an integer. 63 64 The integer is represented using length bytes. An OverflowError is 65 raised if the integer is not representable with the given number of 66 bytes. 67 68 The byteorder argument determines the byte order used to represent the 69 integer. If byteorder is 'big', the most significant byte is at the 70 beginning of the byte array. If byteorder is 'little', the most 71 significant byte is at the end of the byte array. To request the native 72 byte order of the host system, use `sys.byteorder' as the byte order value. 73 74 The signed keyword-only argument determines whether two's complement is 75 used to represent the integer. If signed is False and a negative integer 76 is given, an OverflowError is raised. 77 """ 78 pass 79 80 def __abs__(self, *args, **kwargs): # real signature unknown 81 '''返回绝对值''' 82 """ abs(self) """ 83 pass 84 85 def __add__(self, *args, **kwargs): # real signature unknown 86 """ Return self+value. """ 87 pass 88 89 def __and__(self, *args, **kwargs): # real signature unknown 90 """ Return self&value. """ 91 pass 92 93 def __bool__(self, *args, **kwargs): # real signature unknown 94 """ self != 0 """ 95 pass 96 97 def __ceil__(self, *args, **kwargs): # real signature unknown 98 """ Ceiling of an Integral returns itself. """ 99 pass 100 101 def __divmod__(self, *args, **kwargs): # real signature unknown 102 '''相除，得到商和余数组成的元组''' 103 """ Return divmod(self, value). """ 104 pass 105 106 def __eq__(self, *args, **kwargs): # real signature unknown 107 """ Return self==value. """ 108 pass 109 110 def __float__(self, *args, **kwargs): # real signature unknown 111 '''转换为浮点类型''' 112 """ float(self) """ 113 pass 114 115 def __floordiv__(self, *args, **kwargs): # real signature unknown 116 """ Return self//value. """ 117 pass 118 119 def __floor__(self, *args, **kwargs): # real signature unknown 120 """ Flooring an Integral returns itself. """ 121 pass 122 123 def __format__(self, *args, **kwargs): # real signature unknown 124 pass 125 126 def __getattribute__(self, *args, **kwargs): # real signature unknown 127 '''内部调用 __new__方法或创建对象时传入参数使用''' 128 """ Return getattr(self, name). """ 129 pass 130 131 def __getnewargs__(self, *args, **kwargs): # real signature unknown 132 pass 133 134 def __ge__(self, *args, **kwargs): # real signature unknown 135 """ Return self>=value. """ 136 pass 137 138 def __gt__(self, *args, **kwargs): # real signature unknown 139 """ Return self>value. """ 140 pass 141 142 def __hash__(self, *args, **kwargs): # real signature unknown 143 '''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。''' 144 """ Return hash(self). """ 145 pass 146 147 def __index__(self, *args, **kwargs): # real signature unknown 148 '''用于切片，数字无意义''' 149 """ Return self converted to an integer, if self is suitable for use as an index into a list. """ 150 pass 151 152 def __init__(self, x, base=10): # known special case of int.__init__ 153 '''构造方法，执行 x = 123 或 x = int(10) 时，自动调用，暂时忽略''' 154 """ 155 int(x=0) -> integer 156 int(x, base=10) -> integer 157 158 Convert a number or string to an integer, or return 0 if no arguments 159 are given. If x is a number, return x.__int__(). For floating point 160 numbers, this truncates towards zero. 161 162 If x is not a number or if base is given, then x must be a string, 163 bytes, or bytearray instance representing an integer literal in the 164 given base. The literal can be preceded by '+' or '-' and be surrounded 165 by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. 166 Base 0 means to interpret the base from the string as an integer literal. 167 >>> int('0b100', base=0) 168 4 169 # (copied from class doc) 170 """ 171 pass 172 173 def __int__(self, *args, **kwargs): # real signature unknown 174 '''转换为整数''' 175 """ int(self) """ 176 pass 177 178 def __invert__(self, *args, **kwargs): # real signature unknown 179 """ ~self """ 180 pass 181 182 def __le__(self, *args, **kwargs): # real signature unknown 183 """ Return self<=value. """ 184 pass 185 186 def __lshift__(self, *args, **kwargs): # real signature unknown 187 """ Return self<<value. """ 188 pass 189 190 def __lt__(self, *args, **kwargs): # real signature unknown 191 """ Return self<value. """ 192 pass 193 194 def __mod__(self, *args, **kwargs): # real signature unknown 195 """ Return self%value. """ 196 pass 197 198 def __mul__(self, *args, **kwargs): # real signature unknown 199 """ Return self*value. """ 200 pass 201 202 def __neg__(self, *args, **kwargs): # real signature unknown 203 """ -self """ 204 pass 205 206 @staticmethod # known case of __new__ 207 def __new__(*args, **kwargs): # real signature unknown 208 """ Create and return a new object. See help(type) for accurate signature. """ 209 pass 210 211 def __ne__(self, *args, **kwargs): # real signature unknown 212 """ Return self!=value. """ 213 pass 214 215 def __or__(self, *args, **kwargs): # real signature unknown 216 """ Return self|value. """ 217 pass 218 219 def __pos__(self, *args, **kwargs): # real signature unknown 220 """ +self """ 221 pass 222 223 def __pow__(self, *args, **kwargs): # real signature unknown 224 """ Return pow(self, value, mod). """ 225 pass 226 227 def __radd__(self, *args, **kwargs): # real signature unknown 228 """ Return value+self. """ 229 pass 230 231 def __rand__(self, *args, **kwargs): # real signature unknown 232 """ Return value&self. """ 233 pass 234 235 def __rdivmod__(self, *args, **kwargs): # real signature unknown 236 """ Return divmod(value, self). """ 237 pass 238 239 def __repr__(self, *args, **kwargs): # real signature unknown 240 """ Return repr(self). """ 241 pass 242 243 def __rfloordiv__(self, *args, **kwargs): # real signature unknown 244 """ Return value//self. """ 245 pass 246 247 def __rlshift__(self, *args, **kwargs): # real signature unknown 248 """ Return value<<self. """ 249 pass 250 251 def __rmod__(self, *args, **kwargs): # real signature unknown 252 """ Return value%self. """ 253 pass 254 255 def __rmul__(self, *args, **kwargs): # real signature unknown 256 """ Return value*self. """ 257 pass 258 259 def __ror__(self, *args, **kwargs): # real signature unknown 260 """ Return value|self. """ 261 pass 262 263 def __round__(self, *args, **kwargs): # real signature unknown 264 """ 265 Rounding an Integral returns itself. 266 Rounding with an ndigits argument also returns an integer. 267 """ 268 pass 269 270 def __rpow__(self, *args, **kwargs): # real signature unknown 271 """ Return pow(value, self, mod). """ 272 pass 273 274 def __rrshift__(self, *args, **kwargs): # real signature unknown 275 """ Return value>>self. """ 276 pass 277 278 def __rshift__(self, *args, **kwargs): # real signature unknown 279 """ Return self>>value. """ 280 pass 281 282 def __rsub__(self, *args, **kwargs): # real signature unknown 283 """ Return value-self. """ 284 pass 285 286 def __rtruediv__(self, *args, **kwargs): # real signature unknown 287 """ Return value/self. """ 288 pass 289 290 def __rxor__(self, *args, **kwargs): # real signature unknown 291 """ Return value^self. """ 292 pass 293 294 def __sizeof__(self, *args, **kwargs): # real signature unknown 295 """ Returns size in memory, in bytes """ 296 pass 297 298 def __str__(self, *args, **kwargs): # real signature unknown 299 '''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''' 300 """ Return str(self). """ 301 pass 302 303 def __sub__(self, *args, **kwargs): # real signature unknown 304 """ Return self-value. """ 305 pass 306 307 def __truediv__(self, *args, **kwargs): # real signature unknown 308 """ Return self/value. """ 309 pass 310 311 def __trunc__(self, *args, **kwargs): # real signature unknown 312 """ Truncating an Integral returns itself. """ 313 pass 314 315 def __xor__(self, *args, **kwargs): # real signature unknown 316 """ Return self^value. """ 317 pass 318 319 denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 320 """the denominator of a rational number in lowest terms""" 321 322 imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 323 """the imaginary part of a complex number""" 324 325 numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 326 """the numerator of a rational number in lowest terms""" 327 328 real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 329 """the real part of a complex number"""
以上函数常用的有：
| 函数 | 返回值 ( 描述 ) |
|---|---|
| abs(x) | 返回数字的绝对值，如abs(-10) 返回 10 |
| ceil(x) | 返回数字的上入整数，如math.ceil(4.1) 返回 5 |
|
cmp(x, y) |
如果 x < y 返回 -1, 如果 x == y 返回 0, 如果 x > y 返回 1。 Python 3 已废弃 。使用 使用 (x>y)-(x<y) 替换。 |
| exp(x) | 返回e的x次幂(ex),如math.exp(1) 返回2.718281828459045 |
| fabs(x) | 返回数字的绝对值，如math.fabs(-10) 返回10.0 |
| floor(x) | 返回数字的下舍整数，如math.floor(4.9)返回 4 |
| log(x) | 如math.log(math.e)返回1.0,math.log(100,10)返回2.0 |
| log10(x) | 返回以10为基数的x的对数，如math.log10(100)返回 2.0 |
| max(x1, x2,...) | 返回给定参数的最大值，参数可以为序列。 |
| min(x1, x2,...) | 返回给定参数的最小值，参数可以为序列。 |
| modf(x) | 返回x的整数部分与小数部分，两部分的数值符号与x相同，整数部分以浮点型表示。 |
| pow(x, y) | x**y 运算后的值。 |
| round(x [,n]) | 返回浮点数x的四舍五入值，如给出n值，则代表舍入到小数点后的位数。 |
| sqrt(x) | 返回数字x的平方根，数字可以为负数，返回类型为实数，如math.sqrt(4)返回 2+0j |
布尔值
真或假
1或0
字符串
字符串的表示形式一般为用''或者""来表示，例如'abc'或者"abc"
字符串常用的功能：
- 移除空白
- 分割
- 长度
- 索引
- 切片
1 #!/usr/bin/env python3 2 3 str 4 5 class str(object): 6 """ 7 str(object='') -> str 8 str(bytes_or_buffer[, encoding[, errors]]) -> str 9 10 Create a new string object from the given object. If encoding or 11 errors is specified, then the object must expose a data buffer 12 that will be decoded using the given encoding and error handler. 13 Otherwise, returns the result of object.__str__() (if defined) 14 or repr(object). 15 encoding defaults to sys.getdefaultencoding(). 16 errors defaults to 'strict'. 17 """ 18 def capitalize(self): # real signature unknown; restored from __doc__ 19 '''将字符串的第一个字符转换为大写''' 20 """ 21 S.capitalize() -> str 22 23 Return a capitalized version of S, i.e. make the first character 24 have upper case and the rest lower case. 25 """ 26 return "" 27 28 def casefold(self): # real signature unknown; restored from __doc__ 29 """ 30 S.casefold() -> str 31 32 Return a version of S suitable for caseless comparisons. 33 """ 34 return "" 35 36 def center(self, width, fillchar=None): # real signature unknown; restored from __doc__ 37 '''返回一个指定的宽度 width 居中的字符串，fillchar 为填充的字符，默认为空格。''' 38 """ 39 S.center(width[, fillchar]) -> str 40 41 Return S centered in a string of length width. Padding is 42 done using the specified fill character (default is a space) 43 """ 44 return "" 45 46 def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 47 '''返回 str 在 string 里面出现的次数，如果 beg 或者 end 指定则返回指定范围内 str 出现的次数 48 ''' 49 """ 50 S.count(sub[, start[, end]]) -> int 51 52 Return the number of non-overlapping occurrences of substring sub in 53 string S[start:end]. Optional arguments start and end are 54 interpreted as in slice notation. 55 """ 56 return 0 57 58 def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__ 59 '''以 encoding 指定的编码格式编码字符串，如果出错默认报一个ValueError 的异常，除非 errors 指定的是'ignore'或者'replace''' 60 """ 61 S.encode(encoding='utf-8', errors='strict') -> bytes 62 63 Encode S using the codec registered for encoding. Default encoding 64 is 'utf-8'. errors may be given to set a different error 65 handling scheme. Default is 'strict' meaning that encoding errors raise 66 a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and 67 'xmlcharrefreplace' as well as any other name registered with 68 codecs.register_error that can handle UnicodeEncodeErrors. 69 """ 70 return b"" 71 72 def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__ 73 '''检查字符串是否以 obj 结束，如果beg 或者 end 指定则检查指定的范围内是否以 obj 结束，如果是，返回 True,否则返回 False.''' 74 """ 75 S.endswith(suffix[, start[, end]]) -> bool 76 77 Return True if S ends with the specified suffix, False otherwise. 78 With optional start, test S beginning at that position. 79 With optional end, stop comparing S at that position. 80 suffix can also be a tuple of strings to try. 81 """ 82 return False 83 84 def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__ 85 '''把字符串 string 中的 tab 符号转为空格，tab 符号默认的空格数是 8 。''' 86 """ 87 S.expandtabs(tabsize=8) -> str 88 89 Return a copy of S where all tab characters are expanded using spaces. 90 If tabsize is not given, a tab size of 8 characters is assumed. 91 """ 92 return "" 93 94 def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 95 '''检测 str 是否包含在字符串中 中，如果 beg 和 end 指定范围，则检查是否包含在指定范围内，如果是返回开始的索引值，否则返回-1 ''' 96 97 """ 98 S.find(sub[, start[, end]]) -> int 99 100 Return the lowest index in S where substring sub is found, 101 such that sub is contained within S[start:end]. Optional 102 arguments start and end are interpreted as in slice notation. 103 104 Return -1 on failure. 105 """ 106 return 0 107 108 def format(*args, **kwargs): # known special case of str.format 109 """ 110 S.format(*args, **kwargs) -> str 111 112 Return a formatted version of S, using substitutions from args and kwargs. 113 The substitutions are identified by braces ('{' and '}'). 114 """ 115 pass 116 117 def format_map(self, mapping): # real signature unknown; restored from __doc__ 118 """ 119 S.format_map(mapping) -> str 120 121 Return a formatted version of S, using substitutions from mapping. 122 The substitutions are identified by braces ('{' and '}'). 123 """ 124 return "" 125 126 def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 127 '''跟find()方法一样，只不过如果str不在字符串中会报一个异常.''' 128 """ 129 S.index(sub[, start[, end]]) -> int 130 131 Like S.find() but raise ValueError when the substring is not found. 132 """ 133 return 0 134 135 def isalnum(self): # real signature unknown; restored from __doc__ 136 '''如果字符串至少有一个字符并且所有字符都是字母或数字则返 回 True,否则返回 False''' 137 """ 138 S.isalnum() -> bool 139 140 Return True if all characters in S are alphanumeric 141 and there is at least one character in S, False otherwise. 142 """ 143 return False 144 145 def isalpha(self): # real signature unknown; restored from __doc__ 146 '''如果字符串至少有一个字符并且所有字符都是字母则返回 True, 否则返回 False''' 147 """ 148 S.isalpha() -> bool 149 150 Return True if all characters in S are alphabetic 151 and there is at least one character in S, False otherwise. 152 """ 153 return False 154 155 def isdecimal(self): # real signature unknown; restored from __doc__ 156 '''检查字符串是否只包含十进制字符，如果是返回 true，否则返回 false。''' 157 """ 158 S.isdecimal() -> bool 159 160 Return True if there are only decimal characters in S, 161 False otherwise. 162 """ 163 return False 164 165 def isdigit(self): # real signature unknown; restored from __doc__ 166 '''如果字符串只包含数字则返回 True 否则返回 False..''' 167 """ 168 S.isdigit() -> bool 169 170 Return True if all characters in S are digits 171 and there is at least one character in S, False otherwise. 172 """ 173 return False 174 175 def isidentifier(self): # real signature unknown; restored from __doc__ 176 """ 177 S.isidentifier() -> bool 178 179 Return True if S is a valid identifier according 180 to the language definition. 181 182 Use keyword.iskeyword() to test for reserved identifiers 183 such as "def" and "class". 184 """ 185 return False 186 187 def islower(self): # real signature unknown; restored from __doc__ 188 '''如果字符串中包含至少一个区分大小写的字符，并且所有这些(区分大小写的)字符都是小写，则返回 True，否则返回 False''' 189 """ 190 S.islower() -> bool 191 192 Return True if all cased characters in S are lowercase and there is 193 at least one cased character in S, False otherwise. 194 """ 195 return False 196 197 def isnumeric(self): # real signature unknown; restored from __doc__ 198 '''如果字符串中只包含数字字符，则返回 True，否则返回 False''' 199 """ 200 S.isnumeric() -> bool 201 202 Return True if there are only numeric characters in S, 203 False otherwise. 204 """ 205 return False 206 207 def isprintable(self): # real signature unknown; restored from __doc__ 208 """ 209 S.isprintable() -> bool 210 211 Return True if all characters in S are considered 212 printable in repr() or S is empty, False otherwise. 213 """ 214 return False 215 216 def isspace(self): # real signature unknown; restored from __doc__ 217 '''如果字符串中只包含空格，则返回 True，否则返回 False.''' 218 """ 219 S.isspace() -> bool 220 221 Return True if all characters in S are whitespace 222 and there is at least one character in S, False otherwise. 223 """ 224 return False 225 226 def istitle(self): # real signature unknown; restored from __doc__ 227 '''如果字符串是标题化的(见 title())则返回 True，否则返回 False''' 228 """ 229 S.istitle() -> bool 230 231 Return True if S is a titlecased string and there is at least one 232 character in S, i.e. upper- and titlecase characters may only 233 follow uncased characters and lowercase characters only cased ones. 234 Return False otherwise. 235 """ 236 return False 237 238 def isupper(self): # real signature unknown; restored from __doc__ 239 '''如果字符串中包含至少一个区分大小写的字符，并且所有这些(区分大小写的)字符都是大写，则返回 True，否则返回 False''' 240 """ 241 S.isupper() -> bool 242 243 Return True if all cased characters in S are uppercase and there is 244 at least one cased character in S, False otherwise. 245 """ 246 return False 247 248 def join(self, iterable): # real signature unknown; restored from __doc__ 249 '''以指定字符串作为分隔符，将 seq 中所有的元素(的字符串表示)合并为一个新的字符串''' 250 """ 251 S.join(iterable) -> str 252 253 Return a string which is the concatenation of the strings in the 254 iterable. The separator between elements is S. 255 """ 256 return "" 257 258 def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__ 259 '''返回一个原字符串左对齐,并使用 fillchar 填充至长度 width 的新字符串，fillchar 默认为空格。''' 260 """ 261 S.ljust(width[, fillchar]) -> str 262 263 Return S left-justified in a Unicode string of length width. Padding is 264 done using the specified fill character (default is a space). 265 """ 266 return "" 267 268 def lower(self): # real signature unknown; restored from __doc__ 269 '''转换字符串中所有大写字符为小写.''' 270 """ 271 S.lower() -> str 272 273 Return a copy of the string S converted to lowercase. 274 """ 275 return "" 276 277 def lstrip(self, chars=None): # real signature unknown; restored from __doc__ 278 '''截掉字符串左边的空格''' 279 """ 280 S.lstrip([chars]) -> str 281 282 Return a copy of the string S with leading whitespace removed. 283 If chars is given and not None, remove characters in chars instead. 284 """ 285 return "" 286 287 def maketrans(self, *args, **kwargs): # real signature unknown 288 '''创建字符映射的转换表，对于接受两个参数的最简单的调用方式，第一个参数是字符串，表示需要转换的字符，第二个参数也是字符串表示转换的目标。''' 289 """ 290 Return a translation table usable for str.translate(). 291 292 If there is only one argument, it must be a dictionary mapping Unicode 293 ordinals (integers) or characters to Unicode ordinals, strings or None. 294 Character keys will be then converted to ordinals. 295 If there are two arguments, they must be strings of equal length, and 296 in the resulting dictionary, each character in x will be mapped to the 297 character at the same position in y. If there is a third argument, it 298 must be a string, whose characters will be mapped to None in the result. 299 """ 300 pass 301 302 def partition(self, sep): # real signature unknown; restored from __doc__ 303 """ 304 S.partition(sep) -> (head, sep, tail) 305 306 Search for the separator sep in S, and return the part before it, 307 the separator itself, and the part after it. If the separator is not 308 found, return S and two empty strings. 309 """ 310 pass 311 312 def replace(self, old, new, count=None): # real signature unknown; restored from __doc__ 313 '''把 将字符串中的 str1 替换成 str2,如果 max 指定，则替换不超过 max 次。''' 314 """ 315 S.replace(old, new[, count]) -> str 316 317 Return a copy of S with all occurrences of substring 318 old replaced by new. If the optional argument count is 319 given, only the first count occurrences are replaced. 320 """ 321 return "" 322 323 def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 324 '''类似于 find()函数，不过是从右边开始查找.''' 325 """ 326 S.rfind(sub[, start[, end]]) -> int 327 328 Return the highest index in S where substring sub is found, 329 such that sub is contained within S[start:end]. Optional 330 arguments start and end are interpreted as in slice notation. 331 332 Return -1 on failure. 333 """ 334 return 0 335 336 def rindex(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ 337 '''类似于 index()，不过是从右边开始.''' 338 """ 339 S.rindex(sub[, start[, end]]) -> int 340 341 Like S.rfind() but raise ValueError when the substring is not found. 342 """ 343 return 0 344 345 def rjust(self, width, fillchar=None): # real signature unknown; restored from __doc__ 346 '''返回一个原字符串右对齐,并使用fillchar(默认空格）填充至长度 width 的新字符串''' 347 """ 348 S.rjust(width[, fillchar]) -> str 349 350 Return S right-justified in a string of length width. Padding is 351 done using the specified fill character (default is a space). 352 """ 353 return "" 354 355 def rpartition(self, sep): # real signature unknown; restored from __doc__ 356 """ 357 S.rpartition(sep) -> (head, sep, tail) 358 359 Search for the separator sep in S, starting at the end of S, and return 360 the part before it, the separator itself, and the part after it. If the 361 separator is not found, return two empty strings and S. 362 """ 363 pass 364 365 def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__ 366 367 """ 368 S.rsplit(sep=None, maxsplit=-1) -> list of strings 369 370 Return a list of the words in S, using sep as the 371 delimiter string, starting at the end of the string and 372 working to the front. If maxsplit is given, at most maxsplit 373 splits are done. If sep is not specified, any whitespace string 374 is a separator. 375 """ 376 return [] 377 378 def rstrip(self, chars=None): # real signature unknown; restored from __doc__ 379 '''删除字符串字符串末尾的空格.''' 380 """ 381 S.rstrip([chars]) -> str 382 383 Return a copy of the string S with trailing whitespace removed. 384 If chars is given and not None, remove characters in chars instead. 385 """ 386 return "" 387 388 def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__ 389 390 """ 391 S.split(sep=None, maxsplit=-1) -> list of strings 392 393 Return a list of the words in S, using sep as the 394 delimiter string. If maxsplit is given, at most maxsplit 395 splits are done. If sep is not specified or is None, any 396 whitespace string is a separator and empty strings are 397 removed from the result. 398 """ 399 return [] 400 401 def splitlines(self, keepends=None): # real signature unknown; restored from __doc__ 402 """ 403 S.splitlines([keepends]) -> list of strings 404 405 Return a list of the lines in S, breaking at line boundaries. 406 Line breaks are not included in the resulting list unless keepends 407 is given and true. 408 """ 409 return [] 410 411 def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__ 412 """ 413 S.startswith(prefix[, start[, end]]) -> bool 414 415 Return True if S starts with the specified prefix, False otherwise. 416 With optional start, test S beginning at that position. 417 With optional end, stop comparing S at that position. 418 prefix can also be a tuple of strings to try. 419 """ 420 return False 421 422 def strip(self, chars=None): # real signature unknown; restored from __doc__ 423 '''在字符串上执行 lstrip()和 rstrip()''' 424 """ 425 S.strip([chars]) -> str 426 427 Return a copy of the string S with leading and trailing 428 whitespace removed. 429 If chars is given and not None, remove characters in chars instead. 430 """ 431 return "" 432 433 def swapcase(self): # real signature unknown; restored from __doc__ 434 """ 435 S.swapcase() -> str 436 437 Return a copy of S with uppercase characters converted to lowercase 438 and vice versa. 439 """ 440 return "" 441 442 def title(self): # real signature unknown; restored from __doc__ 443 '''返回"标题化"的字符串,就是说所有单词都是以大写开始，其余字母均为小写(见 istitle())''' 444 """ 445 S.title() -> str 446 447 Return a titlecased version of S, i.e. words start with title case 448 characters, all remaining cased characters have lower case. 449 """ 450 return "" 451 452 def translate(self, table): # real signature unknown; restored from __doc__ 453 """ 454 S.translate(table) -> str 455 456 Return a copy of the string S in which each character has been mapped 457 through the given translation table. The table must implement 458 lookup/indexing via __getitem__, for instance a dictionary or list, 459 mapping Unicode ordinals to Unicode ordinals, strings, or None. If 460 this operation raises LookupError, the character is left untouched. 461 Characters mapped to None are deleted. 462 """ 463 return "" 464 465 def upper(self): # real signature unknown; restored from __doc__ 466 '''转换字符串中的小写字母为大写''' 467 """ 468 S.upper() -> str 469 470 Return a copy of S converted to uppercase. 471 """ 472 return "" 473 474 def zfill(self, width): # real signature unknown; restored from __doc__ 475 '''返回长度为 width 的字符串，原字符串右对齐，前面填充0''' 476 """ 477 S.zfill(width) -> str 478 479 Pad a numeric string S with zeros on the left, to fill a field 480 of the specified width. The string S is never truncated. 481 """ 482 return "" 483 484 def __add__(self, *args, **kwargs): # real signature unknown 485 """ Return self+value. """ 486 pass 487 488 def __contains__(self, *args, **kwargs): # real signature unknown 489 """ Return key in self. """ 490 pass 491 492 def __eq__(self, *args, **kwargs): # real signature unknown 493 """ Return self==value. """ 494 pass 495 496 def __format__(self, format_spec): # real signature unknown; restored from __doc__ 497 """ 498 S.__format__(format_spec) -> str 499 500 Return a formatted version of S as described by format_spec. 501 """ 502 return "" 503 504 def __getattribute__(self, *args, **kwargs): # real signature unknown 505 """ Return getattr(self, name). """ 506 pass 507 508 def __getitem__(self, *args, **kwargs): # real signature unknown 509 """ Return self[key]. """ 510 pass 511 512 def __getnewargs__(self, *args, **kwargs): # real signature unknown 513 pass 514 515 def __ge__(self, *args, **kwargs): # real signature unknown 516 """ Return self>=value. """ 517 pass 518 519 def __gt__(self, *args, **kwargs): # real signature unknown 520 """ Return self>value. """ 521 pass 522 523 def __hash__(self, *args, **kwargs): # real signature unknown 524 """ Return hash(self). """ 525 pass 526 527 def __init__(self, value='', encoding=None, errors='strict'): # known special case of str.__init__ 528 """ 529 str(object='') -> str 530 str(bytes_or_buffer[, encoding[, errors]]) -> str 531 532 Create a new string object from the given object. If encoding or 533 errors is specified, then the object must expose a data buffer 534 that will be decoded using the given encoding and error handler. 535 Otherwise, returns the result of object.__str__() (if defined) 536 or repr(object). 537 encoding defaults to sys.getdefaultencoding(). 538 errors defaults to 'strict'. 539 # (copied from class doc) 540 """ 541 pass 542 543 def __iter__(self, *args, **kwargs): # real signature unknown 544 """ Implement iter(self). """ 545 pass 546 547 def __len__(self, *args, **kwargs): # real signature unknown 548 """ Return len(self). """ 549 pass 550 551 def __le__(self, *args, **kwargs): # real signature unknown 552 """ Return self<=value. """ 553 pass 554 555 def __lt__(self, *args, **kwargs): # real signature unknown 556 """ Return self<value. """ 557 pass 558 559 def __mod__(self, *args, **kwargs): # real signature unknown 560 """ Return self%value. """ 561 pass 562 563 def __mul__(self, *args, **kwargs): # real signature unknown 564 """ Return self*value.n """ 565 pass 566 567 @staticmethod # known case of __new__ 568 def __new__(*args, **kwargs): # real signature unknown 569 """ Create and return a new object. See help(type) for accurate signature. """ 570 pass 571 572 def __ne__(self, *args, **kwargs): # real signature unknown 573 """ Return self!=value. """ 574 pass 575 576 def __repr__(self, *args, **kwargs): # real signature unknown 577 """ Return repr(self). """ 578 pass 579 580 def __rmod__(self, *args, **kwargs): # real signature unknown 581 """ Return value%self. """ 582 pass 583 584 def __rmul__(self, *args, **kwargs): # real signature unknown 585 """ Return self*value. """ 586 pass 587 588 def __sizeof__(self): # real signature unknown; restored from __doc__ 589 """ S.__sizeof__() -> size of S in memory, in bytes """ 590 pass 591 592 def __str__(self, *args, **kwargs): # real signature unknown 593 """ Return str(self). """ 594 pass
以上函数常用的有：
| 序号 | 方法及描述 |
|---|---|
| 1 |
capitalize() |
| 2 |
center(width, fillchar) 返回一个指定的宽度 width 居中的字符串，fillchar 为填充的字符，默认为空格。 |
| 3 |
count(str, beg= 0,end=len(string)) 返回 str 在 string 里面出现的次数，如果 beg 或者 end 指定则返回指定范围内 str 出现的次数 |
| 4 |
decode(encoding='UTF-8',errors='strict') 使用指定编码来解码字符串。默认编码为字符串编码。 |
| 5 |
encode(encoding='UTF-8',errors='strict') 以 encoding 指定的编码格式编码字符串，如果出错默认报一个ValueError 的异常，除非 errors 指定的是'ignore'或者'replace' |
| 6 |
endswith(suffix, beg=0, end=len(string)) |
| 7 |
expandtabs(tabsize=8) 把字符串 string 中的 tab 符号转为空格，tab 符号默认的空格数是 8 。 |
| 8 |
find(str, beg=0 end=len(string)) 检测 str 是否包含在字符串中 中，如果 beg 和 end 指定范围，则检查是否包含在指定范围内，如果是返回开始的索引值，否则返回-1 |
| 9 |
index(str, beg=0, end=len(string)) 跟find()方法一样，只不过如果str不在字符串中会报一个异常. |
| 10 |
isalnum() 如果字符串至少有一个字符并且所有字符都是字母或数字则返 回 True,否则返回 False |
| 11 |
isalpha() 如果字符串至少有一个字符并且所有字符都是字母则返回 True, 否则返回 False |
| 12 |
isdigit() 如果字符串只包含数字则返回 True 否则返回 False.. |
| 13 |
islower() 如果字符串中包含至少一个区分大小写的字符，并且所有这些(区分大小写的)字符都是小写，则返回 True，否则返回 False |
| 14 |
isnumeric() 如果字符串中只包含数字字符，则返回 True，否则返回 False |
| 15 |
isspace() 如果字符串中只包含空格，则返回 True，否则返回 False. |
| 16 |
istitle() 如果字符串是标题化的(见 title())则返回 True，否则返回 False |
| 17 |
isupper() 如果字符串中包含至少一个区分大小写的字符，并且所有这些(区分大小写的)字符都是大写，则返回 True，否则返回 False |
| 18 |
join(seq) 以指定字符串作为分隔符，将 seq 中所有的元素(的字符串表示)合并为一个新的字符串 |
| 19 |
len(string) 返回字符串长度 |
| 20 |
ljust(width[, fillchar]) 返回一个原字符串左对齐,并使用 fillchar 填充至长度 width 的新字符串，fillchar 默认为空格。 |
| 21 |
lower() 转换字符串中所有大写字符为小写. |
| 22 |
lstrip() 截掉字符串左边的空格 |
| 23 |
maketrans() 创建字符映射的转换表，对于接受两个参数的最简单的调用方式，第一个参数是字符串，表示需要转换的字符，第二个参数也是字符串表示转换的目标。 |
| 24 |
max(str) 返回字符串 str 中最大的字母。 |
| 25 |
min(str) 返回字符串 str 中最小的字母。 |
| 26 |
replace(old, new [, max]) 把 将字符串中的 str1 替换成 str2,如果 max 指定，则替换不超过 max 次。 |
| 27 |
rfind(str, beg=0,end=len(string)) 类似于 find()函数，不过是从右边开始查找. |
| 28 |
rindex( str, beg=0, end=len(string)) 类似于 index()，不过是从右边开始. |
| 29 |
rjust(width,[, fillchar]) 返回一个原字符串右对齐,并使用fillchar(默认空格）填充至长度 width 的新字符串 |
| 30 |
rstrip() 删除字符串字符串末尾的空格. |
| 31 |
split(str="", num=string.count(str)) num=string.count(str)) 以 str 为分隔符截取字符串，如果 num 有指定值，则仅截取 num 个子字符串 |
| 32 |
splitlines( num=string.count(' ')) 按照行分隔，返回一个包含各行作为元素的列表，如果 num 指定则仅切片 num 个行. |
| 33 |
startswith(str, beg=0,end=len(string)) 检查字符串是否是以 obj 开头，是则返回 True，否则返回 False。如果beg 和 end 指定值，则在指定范围内检查。 |
| 34 |
strip([chars]) 在字符串上执行 lstrip()和 rstrip() |
| 35 |
swapcase() 将字符串中大写转换为小写，小写转换为大写 |
| 36 |
title() 返回"标题化"的字符串,就是说所有单词都是以大写开始，其余字母均为小写(见 istitle()) |
| 37 |
translate(table, deletechars="") 根据 str 给出的表(包含 256 个字符)转换 string 的字符, 要过滤掉的字符放到 deletechars 参数中 |
| 38 |
upper() 转换字符串中的小写字母为大写 |
| 39 |
zfill (width) 返回长度为 width 的字符串，原字符串右对齐，前面填充0 |
| 40 |
isdecimal() 检查字符串是否只包含十进制字符，如果是返回 true，否则返回 false。 |
列表
序列是Python中最基本的数据结构。序列中的每个元素都分配一个数字 - 它的位置，或索引，第一个索引是0，第二个索引是1，依此类推。
Python有6个序列的内置类型，但最常见的是列表和元组。
序列都可以进行的操作包括索引，切片，加，乘，检查成员。
此外，Python已经内置确定序列的长度以及确定最大和最小的元素的方法。
列表是最常用的Python数据类型，它可以作为一个方括号内的逗号分隔值出现。
列表的数据项不需要具有相同的类型
例如：
list1 = ['alex','king','kangkang','abc',123]
列表的索引方式和字符串一样都是从0开始的：
1 #!/usr/bin/env python3 2 3 list1 = ['alex','king','kangkang','abc',123] 4 5 print(list1[0],list1[3])
运行结果：
1 /Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 /Users/zk/PycharmProjects/old_boy/day02/基本数据类型/列表.py 2 alex abc 3 4 Process finished with exit code 0
列表的基本操作：索引、切片、追加、删除、长度、切片、循环、包含
1 #!/usr/bin/env python3 2 3 # list1 = ['alex','king','kangkang','abc',123] 4 # 5 # print(list1[0],list1[3]) 6 list 7 8 class list(object): 9 """ 10 list() -> new empty list 11 list(iterable) -> new list initialized from iterable's items 12 """ 13 def append(self, p_object): # real signature unknown; restored from __doc__ 14 '''在列表末尾添加新的对象''' 15 """ L.append(object) -> None -- append object to end """ 16 pass 17 18 def clear(self): # real signature unknown; restored from __doc__ 19 '''清除选中的列表''' 20 """ L.clear() -> None -- remove all items from L """ 21 pass 22 23 def copy(self): # real signature unknown; restored from __doc__ 24 '''复制列表''' 25 """ L.copy() -> list -- a shallow copy of L """ 26 return [] 27 28 def count(self, value): # real signature unknown; restored from __doc__ 29 '''统计某个元素在列表中出现的次数''' 30 """ L.count(value) -> integer -- return number of occurrences of value """ 31 return 0 32 33 def extend(self, iterable): # real signature unknown; restored from __doc__ 34 '''在列表末尾一次性追加另一个序列中的多个值（用新列表扩展原来的列表）''' 35 """ L.extend(iterable) -> None -- extend list by appending elements from the iterable """ 36 pass 37 38 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ 39 '''从列表中找出某个值第一个匹配项的索引位置''' 40 """ 41 L.index(value, [start, [stop]]) -> integer -- return first index of value. 42 Raises ValueError if the value is not present. 43 """ 44 return 0 45 46 def insert(self, index, p_object): # real signature unknown; restored from __doc__ 47 '''将对象插入列表''' 48 """ L.insert(index, object) -- insert object before index """ 49 pass 50 51 def pop(self, index=None): # real signature unknown; restored from __doc__ 52 '''移除列表中的一个元素（默认最后一个元素），并且返回该元素的值''' 53 """ 54 L.pop([index]) -> item -- remove and return item at index (default last). 55 Raises IndexError if list is empty or index is out of range. 56 """ 57 pass 58 59 def remove(self, value): # real signature unknown; restored from __doc__ 60 '''移除列表中某个值的第一个匹配项''' 61 """ 62 L.remove(value) -> None -- remove first occurrence of value. 63 Raises ValueError if the value is not present. 64 """ 65 pass 66 67 def reverse(self): # real signature unknown; restored from __doc__ 68 '''反向列表中元素''' 69 """ L.reverse() -- reverse *IN PLACE* """ 70 pass 71 72 def sort(self, key=None, reverse=False): # real signature unknown; restored from __doc__ 73 '''对原列表进行排序''' 74 """ L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE* """ 75 pass 76 77 def __add__(self, *args, **kwargs): # real signature unknown 78 """ Return self+value. """ 79 pass 80 81 def __contains__(self, *args, **kwargs): # real signature unknown 82 """ Return key in self. """ 83 pass 84 85 def __delitem__(self, *args, **kwargs): # real signature unknown 86 """ Delete self[key]. """ 87 pass 88 89 def __eq__(self, *args, **kwargs): # real signature unknown 90 """ Return self==value. """ 91 pass 92 93 def __getattribute__(self, *args, **kwargs): # real signature unknown 94 """ Return getattr(self, name). """ 95 pass 96 97 def __getitem__(self, y): # real signature unknown; restored from __doc__ 98 """ x.__getitem__(y) <==> x[y] """ 99 pass 100 101 def __ge__(self, *args, **kwargs): # real signature unknown 102 """ Return self>=value. """ 103 pass 104 105 def __gt__(self, *args, **kwargs): # real signature unknown 106 """ Return self>value. """ 107 pass 108 109 def __iadd__(self, *args, **kwargs): # real signature unknown 110 """ Implement self+=value. """ 111 pass 112 113 def __imul__(self, *args, **kwargs): # real signature unknown 114 """ Implement self*=value. """ 115 pass 116 117 def __init__(self, seq=()): # known special case of list.__init__ 118 """ 119 list() -> new empty list 120 list(iterable) -> new list initialized from iterable's items 121 # (copied from class doc) 122 """ 123 pass 124 125 def __iter__(self, *args, **kwargs): # real signature unknown 126 """ Implement iter(self). """ 127 pass 128 129 def __len__(self, *args, **kwargs): # real signature unknown 130 """ Return len(self). """ 131 pass 132 133 def __le__(self, *args, **kwargs): # real signature unknown 134 """ Return self<=value. """ 135 pass 136 137 def __lt__(self, *args, **kwargs): # real signature unknown 138 """ Return self<value. """ 139 pass 140 141 def __mul__(self, *args, **kwargs): # real signature unknown 142 """ Return self*value.n """ 143 pass 144 145 @staticmethod # known case of __new__ 146 def __new__(*args, **kwargs): # real signature unknown 147 """ Create and return a new object. See help(type) for accurate signature. """ 148 pass 149 150 def __ne__(self, *args, **kwargs): # real signature unknown 151 """ Return self!=value. """ 152 pass 153 154 def __repr__(self, *args, **kwargs): # real signature unknown 155 """ Return repr(self). """ 156 pass 157 158 def __reversed__(self): # real signature unknown; restored from __doc__ 159 """ L.__reversed__() -- return a reverse iterator over the list """ 160 pass 161 162 def __rmul__(self, *args, **kwargs): # real signature unknown 163 """ Return self*value. """ 164 pass 165 166 def __setitem__(self, *args, **kwargs): # real signature unknown 167 """ Set self[key] to value. """ 168 pass 169 170 def __sizeof__(self): # real signature unknown; restored from __doc__ 171 """ L.__sizeof__() -- size of L in memory, in bytes """ 172 pass 173 174 __hash__ = None
以上常用函数：
| 序号 | 方法 |
|---|---|
| 1 | list.append(obj) 在列表末尾添加新的对象 |
| 2 | list.count(obj) 统计某个元素在列表中出现的次数 |
| 3 | list.extend(seq) 在列表末尾一次性追加另一个序列中的多个值（用新列表扩展原来的列表） |
| 4 | list.index(obj) 从列表中找出某个值第一个匹配项的索引位置 |
| 5 | list.insert(index, obj) 将对象插入列表 |
| 6 | list.pop(obj=list[-1]) 移除列表中的一个元素（默认最后一个元素），并且返回该元素的值 |
| 7 | list.remove(obj) 移除列表中某个值的第一个匹配项 |
| 8 | list.reverse() 反向列表中元素 |
| 9 | list.sort([func]) 对原列表进行排序 |
| 10 | list.clear() 清空列表 |
| 11 | list.copy() 复制列表 |
元组
Python 的元组与列表类似，不同之处在于元组的元素不能修改。
元组使用小括号，列表使用方括号。
元组创建很简单，只需要在括号中添加元素，并使用逗号隔开即可。
tup1 = ('alex','king','kangkang','abc',123)
1 #!/usr/bin/env python3 2 3 # tup1 = ('alex','king','kangkang','abc',123) 4 tuple 5 6 class tuple(object): 7 """ 8 tuple() -> empty tuple 9 tuple(iterable) -> tuple initialized from iterable's items 10 11 If the argument is a tuple, the return value is the same object. 12 """ 13 def count(self, value): # real signature unknown; restored from __doc__ 14 '''统计某个元素在元组中出现的次数''' 15 """ T.count(value) -> integer -- return number of occurrences of value """ 16 return 0 17 18 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ 19 '''从元组中找出某个值第一个匹配项的索引位置''' 20 """ 21 T.index(value, [start, [stop]]) -> integer -- return first index of value. 22 Raises ValueError if the value is not present. 23 """ 24 return 0 25 26 def __add__(self, *args, **kwargs): # real signature unknown 27 """ Return self+value. """ 28 pass 29 30 def __contains__(self, *args, **kwargs): # real signature unknown 31 """ Return key in self. """ 32 pass 33 34 def __eq__(self, *args, **kwargs): # real signature unknown 35 """ Return self==value. """ 36 pass 37 38 def __getattribute__(self, *args, **kwargs): # real signature unknown 39 """ Return getattr(self, name). """ 40 pass 41 42 def __getitem__(self, *args, **kwargs): # real signature unknown 43 """ Return self[key]. """ 44 pass 45 46 def __getnewargs__(self, *args, **kwargs): # real signature unknown 47 pass 48 49 def __ge__(self, *args, **kwargs): # real signature unknown 50 """ Return self>=value. """ 51 pass 52 53 def __gt__(self, *args, **kwargs): # real signature unknown 54 """ Return self>value. """ 55 pass 56 57 def __hash__(self, *args, **kwargs): # real signature unknown 58 """ Return hash(self). """ 59 pass 60 61 def __init__(self, seq=()): # known special case of tuple.__init__ 62 """ 63 tuple() -> empty tuple 64 tuple(iterable) -> tuple initialized from iterable's items 65 66 If the argument is a tuple, the return value is the same object. 67 # (copied from class doc) 68 """ 69 pass 70 71 def __iter__(self, *args, **kwargs): # real signature unknown 72 """ Implement iter(self). """ 73 pass 74 75 def __len__(self, *args, **kwargs): # real signature unknown 76 '''计算元组元素个数。''' 77 """ Return len(self). """ 78 pass 79 80 def __le__(self, *args, **kwargs): # real signature unknown 81 """ Return self<=value. """ 82 pass 83 84 def __lt__(self, *args, **kwargs): # real signature unknown 85 """ Return self<value. """ 86 pass 87 88 def __mul__(self, *args, **kwargs): # real signature unknown 89 """ Return self*value.n """ 90 pass 91 92 @staticmethod # known case of __new__ 93 def __new__(*args, **kwargs): # real signature unknown 94 """ Create and return a new object. See help(type) for accurate signature. """ 95 pass 96 97 def __ne__(self, *args, **kwargs): # real signature unknown 98 """ Return self!=value. """ 99 pass 100 101 def __repr__(self, *args, **kwargs): # real signature unknown 102 """ Return repr(self). """ 103 pass 104 105 def __rmul__(self, *args, **kwargs): # real signature unknown 106 """ Return self*value. """ 107 pass
字典
字典是另一种可变容器模型，且可存储任意类型对象。
字典的每个键值(key=>value)对用冒号(:)分割，每个对之间用逗号(,)分割，整个字典包括在花括号({})中 ,格式如下所示：
d = {key1 : value1, key2 : value2 }
键必须是唯一的，但值则不必。
值可以取任何数据类型，但键必须是不可变的，如字符串，数字或元组。
1 #!/usr/bin/env python3 2 3 dic1 = { 4 'alex':'good', 5 'wuSIR':'good', 6 'wb':'DSB' 7 }
取值：
1 #!/usr/bin/env python3 2 3 dic1 = { 4 'alex':'good', 5 'wuSIR':'good', 6 'wb':'DSB' 7 } 8 9 print(dic1['wb'],dic1['wuSIR'])
结果：
1 /Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 /Users/zk/PycharmProjects/old_boy/day02/基本数据类型/字典.py 2 DSB good 3 4 Process finished with exit code 0
使用方法：索引、新增、删除、键、值、键值对、循环、长度
1 #!/usr/bin/env python3 2 3 dic1 = { 4 'alex':'good', 5 'wuSIR':'good', 6 'wb':'DSB' 7 } 8 9 print(dic1['wb'],dic1['wuSIR']) 10 11 dict 12 13 class dict(object): 14 """ 15 dict() -> new empty dictionary 16 dict(mapping) -> new dictionary initialized from a mapping object's 17 (key, value) pairs 18 dict(iterable) -> new dictionary initialized as if via: 19 d = {} 20 for k, v in iterable: 21 d[k] = v 22 dict(**kwargs) -> new dictionary initialized with the name=value pairs 23 in the keyword argument list. For example: dict(one=1, two=2) 24 """ 25 def clear(self): # real signature unknown; restored from __doc__ 26 '''清除内容''' 27 """ D.clear() -> None. Remove all items from D. """ 28 pass 29 30 def copy(self): # real signature unknown; restored from __doc__ 31 '''浅拷贝''' 32 """ D.copy() -> a shallow copy of D """ 33 pass 34 35 @staticmethod # known case 36 def fromkeys(*args, **kwargs): # real signature unknown 37 """ Returns a new dict with keys from iterable and values equal to value. """ 38 pass 39 40 def get(self, k, d=None): # real signature unknown; restored from __doc__ 41 '''根据key获取值，d是默认值''' 42 """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """ 43 pass 44 45 def items(self): # real signature unknown; restored from __doc__ 46 '''所有项的列表形式''' 47 """ D.items() -> a set-like object providing a view on D's items """ 48 pass 49 50 def keys(self): # real signature unknown; restored from __doc__ 51 """ 所有的key列表 """ 52 """ D.keys() -> a set-like object providing a view on D's keys """ 53 pass 54 55 def pop(self, k, d=None): # real signature unknown; restored from __doc__ 56 """ 获取并在字典中移除 """ 57 """ 58 D.pop(k[,d]) -> v, remove specified key and return the corresponding value. 59 If key is not found, d is returned if given, otherwise KeyError is raised 60 """ 61 pass 62 63 def popitem(self): # real signature unknown; restored from __doc__ 64 '''获取并在字典中移除''' 65 """ 66 D.popitem() -> (k, v), remove and return some (key, value) pair as a 67 2-tuple; but raise KeyError if D is empty. 68 """ 69 pass 70 71 def setdefault(self, k, d=None): # real signature unknown; restored from __doc__ 72 '''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''' 73 """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """ 74 pass 75 76 def update(self, E=None, **F): # known special case of dict.update 77 '''更新''' 78 """ 79 D.update([E, ]**F) -> None. Update D from dict/iterable E and F. 80 If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] 81 If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v 82 In either case, this is followed by: for k in F: D[k] = F[k] 83 """ 84 pass 85 86 def values(self): # real signature unknown; restored from __doc__ 87 '''所有的值''' 88 """ D.values() -> an object providing a view on D's values """ 89 pass 90 91 def __contains__(self, *args, **kwargs): # real signature unknown 92 """ True if D has a key k, else False. """ 93 pass 94 95 def __delitem__(self, *args, **kwargs): # real signature unknown 96 """ Delete self[key]. """ 97 pass 98 99 def __eq__(self, *args, **kwargs): # real signature unknown 100 """ Return self==value. """ 101 pass 102 103 def __getattribute__(self, *args, **kwargs): # real signature unknown 104 """ Return getattr(self, name). """ 105 pass 106 107 def __getitem__(self, y): # real signature unknown; restored from __doc__ 108 """ x.__getitem__(y) <==> x[y] """ 109 pass 110 111 def __ge__(self, *args, **kwargs): # real signature unknown 112 """ Return self>=value. """ 113 pass 114 115 def __gt__(self, *args, **kwargs): # real signature unknown 116 """ Return self>value. """ 117 pass 118 119 def __init__(self, seq=None, **kwargs): # known special case of dict.__init__ 120 """ 121 dict() -> new empty dictionary 122 dict(mapping) -> new dictionary initialized from a mapping object's 123 (key, value) pairs 124 dict(iterable) -> new dictionary initialized as if via: 125 d = {} 126 for k, v in iterable: 127 d[k] = v 128 dict(**kwargs) -> new dictionary initialized with the name=value pairs 129 in the keyword argument list. For example: dict(one=1, two=2) 130 # (copied from class doc) 131 """ 132 pass 133 134 def __iter__(self, *args, **kwargs): # real signature unknown 135 """ Implement iter(self). """ 136 pass 137 138 def __len__(self, *args, **kwargs): # real signature unknown 139 """ Return len(self). """ 140 pass 141 142 def __le__(self, *args, **kwargs): # real signature unknown 143 """ Return self<=value. """ 144 pass 145 146 def __lt__(self, *args, **kwargs): # real signature unknown 147 """ Return self<value. """ 148 pass 149 150 @staticmethod # known case of __new__ 151 def __new__(*args, **kwargs): # real signature unknown 152 """ Create and return a new object. See help(type) for accurate signature. """ 153 pass 154 155 def __ne__(self, *args, **kwargs): # real signature unknown 156 """ Return self!=value. """ 157 pass 158 159 def __repr__(self, *args, **kwargs): # real signature unknown 160 """ Return repr(self). """ 161 pass 162 163 def __setitem__(self, *args, **kwargs): # real signature unknown 164 """ Set self[key] to value. """ 165 pass 166 167 def __sizeof__(self): # real signature unknown; restored from __doc__ 168 """ D.__sizeof__() -> size of D in memory, in bytes """ 169 pass 170 171 __hash__ = None
内置函数使用方法：
1 #!/usr/bin/env python3 2 3 dic1 = { 4 'alex':'good', 5 'wuSIR':'good', 6 'wb':'DSB' 7 } 8 9 print(len(dic1)) #计算字典元素个数，即键的总数 10 11 print(str(dic1)) #输出字典以可打印的字符串表示 12 13 print(type(dic1)) #返回输入的变量类型，如果变量是字典就返回字典类型
运行结果：
1 /Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 /Users/zk/PycharmProjects/old_boy/day02/基本数据类型/dic.py 2 3 3 {'wuSIR': 'good', 'alex': 'good', 'wb': 'DSB'} 4 <class 'dict'> 5 6 Process finished with exit code 0
在字典中包含的常用内置方法：
| 序号 | 函数及描述 |
|---|---|
| 1 | radiansdict.clear() 删除字典内所有元素 |
| 2 | radiansdict.copy() 返回一个字典的浅复制 |
| 3 | radiansdict.fromkeys() 创建一个新字典，以序列seq中元素做字典的键，val为字典所有键对应的初始值 |
| 4 | radiansdict.get(key, default=None) 返回指定键的值，如果值不在字典中返回default值 |
| 5 | key in dict 如果键在字典dict里返回true，否则返回false |
| 6 | radiansdict.items() 以列表返回可遍历的(键, 值) 元组数组 |
| 7 | radiansdict.keys() 以列表返回一个字典所有的键 |
| 8 | radiansdict.setdefault(key, default=None) 和get()类似, 但如果键不存在于字典中，将会添加键并将值设为default |
| 9 | radiansdict.update(dict2) 把字典dict2的键/值对更新到dict里 |
| 10 | radiansdict.values() 以列表返回字典中的所有值 |