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  • Python基础之【第二篇】

    一、作用域

    对作用域来说,只要变量在内存里面存在就可以使用:

    1 if 1==1:
    2     name = 'saneri'
    3 print  name

    二、三元运算

    result =  值1  if  条件  else  值2

    如果条件为真:result = 值1
    如果条件为假:result = 值2

    实例:

    a = 1
    b = 2
    c = a if a > 1 else b   # 如果a大于1的话,c=a,否则c=b

    三、进制

    • 二进制,01
    • 八进制,01234567
    • 十进制,0123456789
    • 十六进制,0123456789ABCDE

     对于Python 一切事物都是对象,对象基于类创建.类里面保存了对象的方法和功能:

     通过type可以查看对象的类型
     dir(类型名)查看类中提供的所有功能
     help(类型名) 查看类中所有详细的功能
     help(类型名.功能名) 查看类中某功能的详细信息.

    dir(list) 
    私有方法'__add__', '__class__', '__contains__'     可能有多种执行方式
    
    非内置方法: 'append', 'count', 'extend', 'index', 'insert'  只有一种执行方式,通过对象.方法来调用.

    一、整数

    创建数字方法
    i = 10
    i = int(10)
    i = int("10",base=2)

    1 divmod(10,3)  求商和余数  ---》分页
    2 all()         接收一个序列,判断,所有值都是真,返回真,负责返回假.
    3 any()         只要有一个是真,就是真.
    class 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"""
    int

    二、长整型

    可能如:2147483649、9223372036854775807

    每个长整型都具备如下功能:

    class long(object):
        """
        long(x=0) -> long
        long(x, base=10) -> long
        
        Convert a number or string to a long integer, or return 0L if no arguments
        are given.  If x is floating point, the conversion truncates towards zero.
        
        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)
        4L
        """
        def bit_length(self): # real signature unknown; restored from __doc__
            """
            long.bit_length() -> int or long
            
            Number of bits necessary to represent self in binary.
            >>> bin(37L)
            '0b100101'
            >>> (37L).bit_length()
            6
            """
            return 0
    
        def conjugate(self, *args, **kwargs): # real signature unknown
            """ Returns self, the complex conjugate of any long. """
            pass
    
        def __abs__(self): # real signature unknown; restored from __doc__
            """ x.__abs__() <==> abs(x) """
            pass
    
        def __add__(self, y): # real signature unknown; restored from __doc__
            """ x.__add__(y) <==> x+y """
            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 __coerce__(self, y): # real signature unknown; restored from __doc__
            """ x.__coerce__(y) <==> coerce(x, y) """
            pass
    
        def __divmod__(self, y): # real signature unknown; restored from __doc__
            """ x.__divmod__(y) <==> divmod(x, y) """
            pass
    
        def __div__(self, y): # real signature unknown; restored from __doc__
            """ x.__div__(y) <==> x/y """
            pass
    
        def __float__(self): # real signature unknown; restored from __doc__
            """ x.__float__() <==> float(x) """
            pass
    
        def __floordiv__(self, y): # real signature unknown; restored from __doc__
            """ x.__floordiv__(y) <==> x//y """
            pass
    
        def __format__(self, *args, **kwargs): # real signature unknown
            pass
    
        def __getattribute__(self, name): # real signature unknown; restored from __doc__
            """ x.__getattribute__('name') <==> x.name """
            pass
    
        def __getnewargs__(self, *args, **kwargs): # real signature unknown
            pass
    
        def __hash__(self): # real signature unknown; restored from __doc__
            """ x.__hash__() <==> hash(x) """
            pass
    
        def __hex__(self): # real signature unknown; restored from __doc__
            """ x.__hex__() <==> hex(x) """
            pass
    
        def __index__(self): # real signature unknown; restored from __doc__
            """ x[y:z] <==> x[y.__index__():z.__index__()] """
            pass
    
        def __init__(self, x=0): # real signature unknown; restored from __doc__
            pass
    
        def __int__(self): # real signature unknown; restored from __doc__
            """ x.__int__() <==> int(x) """
            pass
    
        def __invert__(self): # real signature unknown; restored from __doc__
            """ x.__invert__() <==> ~x """
            pass
    
        def __long__(self): # real signature unknown; restored from __doc__
            """ x.__long__() <==> long(x) """
            pass
    
        def __lshift__(self, y): # real signature unknown; restored from __doc__
            """ x.__lshift__(y) <==> x<<y """
            pass
    
        def __mod__(self, y): # real signature unknown; restored from __doc__
            """ x.__mod__(y) <==> x%y """
            pass
    
        def __mul__(self, y): # real signature unknown; restored from __doc__
            """ x.__mul__(y) <==> x*y """
            pass
    
        def __neg__(self): # real signature unknown; restored from __doc__
            """ x.__neg__() <==> -x """
            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 __nonzero__(self): # real signature unknown; restored from __doc__
            """ x.__nonzero__() <==> x != 0 """
            pass
    
        def __oct__(self): # real signature unknown; restored from __doc__
            """ x.__oct__() <==> oct(x) """
            pass
    
        def __or__(self, y): # real signature unknown; restored from __doc__
            """ x.__or__(y) <==> x|y """
            pass
    
        def __pos__(self): # real signature unknown; restored from __doc__
            """ x.__pos__() <==> +x """
            pass
    
        def __pow__(self, y, z=None): # real signature unknown; restored from __doc__
            """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """
            pass
    
        def __radd__(self, y): # real signature unknown; restored from __doc__
            """ x.__radd__(y) <==> y+x """
            pass
    
        def __rand__(self, y): # real signature unknown; restored from __doc__
            """ x.__rand__(y) <==> y&x """
            pass
    
        def __rdivmod__(self, y): # real signature unknown; restored from __doc__
            """ x.__rdivmod__(y) <==> divmod(y, x) """
            pass
    
        def __rdiv__(self, y): # real signature unknown; restored from __doc__
            """ x.__rdiv__(y) <==> y/x """
            pass
    
        def __repr__(self): # real signature unknown; restored from __doc__
            """ x.__repr__() <==> repr(x) """
            pass
    
        def __rfloordiv__(self, y): # real signature unknown; restored from __doc__
            """ x.__rfloordiv__(y) <==> y//x """
            pass
    
        def __rlshift__(self, y): # real signature unknown; restored from __doc__
            """ x.__rlshift__(y) <==> y<<x """
            pass
    
        def __rmod__(self, y): # real signature unknown; restored from __doc__
            """ x.__rmod__(y) <==> y%x """
            pass
    
        def __rmul__(self, y): # real signature unknown; restored from __doc__
            """ x.__rmul__(y) <==> y*x """
            pass
    
        def __ror__(self, y): # real signature unknown; restored from __doc__
            """ x.__ror__(y) <==> y|x """
            pass
    
        def __rpow__(self, x, z=None): # real signature unknown; restored from __doc__
            """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
            pass
    
        def __rrshift__(self, y): # real signature unknown; restored from __doc__
            """ x.__rrshift__(y) <==> y>>x """
            pass
    
        def __rshift__(self, y): # real signature unknown; restored from __doc__
            """ x.__rshift__(y) <==> x>>y """
            pass
    
        def __rsub__(self, y): # real signature unknown; restored from __doc__
            """ x.__rsub__(y) <==> y-x """
            pass
    
        def __rtruediv__(self, y): # real signature unknown; restored from __doc__
            """ x.__rtruediv__(y) <==> y/x """
            pass
    
        def __rxor__(self, y): # real signature unknown; restored from __doc__
            """ x.__rxor__(y) <==> y^x """
            pass
    
        def __sizeof__(self, *args, **kwargs): # real signature unknown
            """ Returns size in memory, in bytes """
            pass
    
        def __str__(self): # real signature unknown; restored from __doc__
            """ x.__str__() <==> str(x) """
            pass
    
        def __sub__(self, y): # real signature unknown; restored from __doc__
            """ x.__sub__(y) <==> x-y """
            pass
    
        def __truediv__(self, y): # real signature unknown; restored from __doc__
            """ x.__truediv__(y) <==> x/y """
            pass
    
        def __trunc__(self, *args, **kwargs): # real signature unknown
            """ Truncating an Integral returns itself. """
            pass
    
        def __xor__(self, y): # real signature unknown; restored from __doc__
            """ x.__xor__(y) <==> x^y """
            pass
    
        denominator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the denominator of a rational number in lowest terms"""
    
        imag = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the imaginary part of a complex number"""
    
        numerator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the numerator of a rational number in lowest terms"""
    
        real = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the real part of a complex number"""
    long

    三、浮点型

    如:3.14、2.88

    每个浮点型都具备如下功能:

    class float(object):
        """
        float(x) -> floating point number
        
        Convert a string or number to a floating point number, if possible.
        """
        def as_integer_ratio(self):   
            """ 获取改值的最简比 """
            """
            float.as_integer_ratio() -> (int, int)
    
            Return a pair of integers, whose ratio is exactly equal to the original
            float and with a positive denominator.
            Raise OverflowError on infinities and a ValueError on NaNs.
    
            >>> (10.0).as_integer_ratio()
            (10, 1)
            >>> (0.0).as_integer_ratio()
            (0, 1)
            >>> (-.25).as_integer_ratio()
            (-1, 4)
            """
            pass
    
        def conjugate(self, *args, **kwargs): # real signature unknown
            """ Return self, the complex conjugate of any float. """
            pass
    
        def fromhex(self, string):   
            """ 将十六进制字符串转换成浮点型 """
            """
            float.fromhex(string) -> float
            
            Create a floating-point number from a hexadecimal string.
            >>> float.fromhex('0x1.ffffp10')
            2047.984375
            >>> float.fromhex('-0x1p-1074')
            -4.9406564584124654e-324
            """
            return 0.0
    
        def hex(self):   
            """ 返回当前值的 16 进制表示 """
            """
            float.hex() -> string
            
            Return a hexadecimal representation of a floating-point number.
            >>> (-0.1).hex()
            '-0x1.999999999999ap-4'
            >>> 3.14159.hex()
            '0x1.921f9f01b866ep+1'
            """
            return ""
    
        def is_integer(self, *args, **kwargs): # real signature unknown
            """ Return True if the float is an integer. """
            pass
    
        def __abs__(self):   
            """ x.__abs__() <==> abs(x) """
            pass
    
        def __add__(self, y):   
            """ x.__add__(y) <==> x+y """
            pass
    
        def __coerce__(self, y):   
            """ x.__coerce__(y) <==> coerce(x, y) """
            pass
    
        def __divmod__(self, y):   
            """ x.__divmod__(y) <==> divmod(x, y) """
            pass
    
        def __div__(self, y):   
            """ x.__div__(y) <==> x/y """
            pass
    
        def __eq__(self, y):   
            """ x.__eq__(y) <==> x==y """
            pass
    
        def __float__(self):   
            """ x.__float__() <==> float(x) """
            pass
    
        def __floordiv__(self, y):   
            """ x.__floordiv__(y) <==> x//y """
            pass
    
        def __format__(self, format_spec):   
            """
            float.__format__(format_spec) -> string
            
            Formats the float according to format_spec.
            """
            return ""
    
        def __getattribute__(self, name):   
            """ x.__getattribute__('name') <==> x.name """
            pass
    
        def __getformat__(self, typestr):   
            """
            float.__getformat__(typestr) -> string
            
            You probably don't want to use this function.  It exists mainly to be
            used in Python's test suite.
            
            typestr must be 'double' or 'float'.  This function returns whichever of
            'unknown', 'IEEE, big-endian' or 'IEEE, little-endian' best describes the
            format of floating point numbers used by the C type named by typestr.
            """
            return ""
    
        def __getnewargs__(self, *args, **kwargs): # real signature unknown
            pass
    
        def __ge__(self, y):   
            """ x.__ge__(y) <==> x>=y """
            pass
    
        def __gt__(self, y):   
            """ x.__gt__(y) <==> x>y """
            pass
    
        def __hash__(self):   
            """ x.__hash__() <==> hash(x) """
            pass
    
        def __init__(self, x):   
            pass
    
        def __int__(self):   
            """ x.__int__() <==> int(x) """
            pass
    
        def __le__(self, y):   
            """ x.__le__(y) <==> x<=y """
            pass
    
        def __long__(self):   
            """ x.__long__() <==> long(x) """
            pass
    
        def __lt__(self, y):   
            """ x.__lt__(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 __ne__(self, y):   
            """ x.__ne__(y) <==> x!=y """
            pass
    
        def __nonzero__(self):   
            """ x.__nonzero__() <==> x != 0 """
            pass
    
        def __pos__(self):   
            """ x.__pos__() <==> +x """
            pass
    
        def __pow__(self, y, z=None):   
            """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """
            pass
    
        def __radd__(self, y):   
            """ x.__radd__(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):   
            """ x.__repr__() <==> repr(x) """
            pass
    
        def __rfloordiv__(self, y):   
            """ x.__rfloordiv__(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 __rpow__(self, x, z=None):   
            """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
            pass
    
        def __rsub__(self, y):   
            """ x.__rsub__(y) <==> y-x """
            pass
    
        def __rtruediv__(self, y):   
            """ x.__rtruediv__(y) <==> y/x """
            pass
    
        def __setformat__(self, typestr, fmt):   
            """
            float.__setformat__(typestr, fmt) -> None
            
            You probably don't want to use this function.  It exists mainly to be
            used in Python's test suite.
            
            typestr must be 'double' or 'float'.  fmt must be one of 'unknown',
            'IEEE, big-endian' or 'IEEE, little-endian', and in addition can only be
            one of the latter two if it appears to match the underlying C reality.
            
            Override the automatic determination of C-level floating point type.
            This affects how floats are converted to and from binary strings.
            """
            pass
    
        def __str__(self):   
            """ x.__str__() <==> str(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): # real signature unknown
            """ Return the Integral closest to x between 0 and x. """
            pass
    
        imag = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the imaginary part of a complex number"""
    
        real = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
        """the real part of a complex number"""
    float
    _hash__   在字典查找中,哈希值用于快速比较字典的键
    __hex__   """ 返回当前数的 十六进制 表示 """                  
    __oct__   返回改值的 八进制 表示 """

    四、字符串

    如:'saneri'、'abcd'

    每个字符串都具备如下功能:  

      1 """
      2     str(object='') -> string
      3     
      4     Return a nice string representation of the object.
      5     If the argument is a string, the return value is the same object.
      6     """
      7     def capitalize(self):  
      8         """ 首字母变大写 """
      9         """
     10         S.capitalize() -> string
     11         
     12         Return a copy of the string S with only its first character
     13         capitalized.
     14         """
     15         return ""
     16      
     17     def center(self, width, fillchar=None):  
     18         """ 内容居中,width:总长度;fillchar:空白处填充内容,默认无 """
     19         """
     20         S.center(width[, fillchar]) -> string
     21        >>> s = "alex" 
     22         >>> s.center(30, "*")    
     23            '*************alex*************'
     24         Return S centered in a string of length width. Padding is
     25         done using the specified fill character (default is a space)
     26         """
     27         return ""
     28 
     29     def count(self, sub, start=None, end=None):  
     30         """ 子序列个数 """
     31         """
     32         S.count(sub[, start[, end]]) -> int
     33         s.count("a",0,5)  start,end找,下标的位置
     34         Return the number of non-overlapping occurrences of substring sub in
     35         string S[start:end].  Optional arguments start and end are interpreted
     36         as in slice notation.
     37         """
     38         return 0
     39 
     40     def decode(self, encoding=None, errors=None):  
     41         """ 解码"""
     42         """
     43         S.decode([encoding[,errors]]) -> object
     44         
     45         Decodes S using the codec registered for encoding. encoding defaults
     46         to the default encoding. errors may be given to set a different error
     47         handling scheme. Default is 'strict' meaning that encoding errors raise
     48         a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
     49         as well as any other name registered with codecs.register_error that is
     50         able to handle UnicodeDecodeErrors.
     51         """
     52         return object()
     53 
     54     def encode(self, encoding=None, errors=None):  
     55         """ 编码,针对unicode """
     56         """
     57         S.encode([encoding[,errors]]) -> object
     58         
     59         Encodes S using the codec registered for encoding. encoding defaults
     60         to the default encoding. errors may be given to set a different error
     61         handling scheme. Default is 'strict' meaning that encoding errors raise
     62         a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
     63         'xmlcharrefreplace' as well as any other name registered with
     64         codecs.register_error that is able to handle UnicodeEncodeErrors.
     65         """
     66         return object()
     67 
     68     def endswith(self, suffix, start=None, end=None):  
     69         """ 是否以 xxx 结束 """
     70         """
     71         S.endswith(suffix[, start[, end]]) -> bool
     72         
     73         Return True if S ends with the specified suffix, False otherwise.
     74         With optional start, test S beginning at that position.
     75         With optional end, stop comparing S at that position.
     76         suffix can also be a tuple of strings to try.
     77         """
     78         return False
     79 
     80     def expandtabs(self, tabsize=None):  
     81         """ 将tab转换成空格,默认一个tab转换成8个空格 """
     82         """
     83         S.expandtabs([tabsize]) -> string
     84         
     85         Return a copy of S where all tab characters are expanded using spaces.
     86         If tabsize is not given, a tab size of 8 characters is assumed.
     87         """
     88         return ""
     89 
     90     def find(self, sub, start=None, end=None):  
     91         """ 寻找子序列位置,如果没找到,则异常 """
     92         """
     93         S.find(sub [,start [,end]]) -> int
     94         
     95         Return the lowest index in S where substring sub is found,
     96         such that sub is contained within S[start:end].  Optional
     97         arguments start and end are interpreted as in slice notation.
     98         
     99         Return -1 on failure.
    100         """
    101         return 0
    102 
    103     def format(*args, **kwargs): # known special case of str.format
    104         """ 字符串格式化,动态参数,将函数式编程时细说 """
    105         """
    106         S.format(*args, **kwargs) -> string
    107         
    108         Return a formatted version of S, using substitutions from args and kwargs.
    109         The substitutions are identified by braces ('{' and '}').
    110         """
    111         pass
    112 
    113     def index(self, sub, start=None, end=None):  
    114         """ 子序列位置,如果没找到,则返回-1  """
    115         S.index(sub [,start [,end]]) -> int
    116         
    117         Like S.find() but raise ValueError when the substring is not found.
    118         """
    119         return 0
    120 
    121     def isalnum(self):  
    122         """ 是否是字母和数字 """
    123         """
    124         S.isalnum() -> bool
    125         
    126         Return True if all characters in S are alphanumeric
    127         and there is at least one character in S, False otherwise.
    128         """
    129         return False
    130 
    131     def isalpha(self):  
    132         """ 是否是字母 """
    133         """
    134         S.isalpha() -> bool
    135         
    136         Return True if all characters in S are alphabetic
    137         and there is at least one character in S, False otherwise.
    138         """
    139         return False
    140 
    141     def isdigit(self):  
    142         """ 是否是数字 """
    143         """
    144         S.isdigit() -> bool
    145         
    146         Return True if all characters in S are digits
    147         and there is at least one character in S, False otherwise.
    148         """
    149         return False
    150 
    151     def islower(self):  
    152         """ 是否小写 """
    153         """
    154         S.islower() -> bool
    155         
    156         Return True if all cased characters in S are lowercase and there is
    157         at least one cased character in S, False otherwise.
    158         """
    159         return False
    160 
    161     def isspace(self):  
    162         """
    163         S.isspace() -> bool
    164         
    165         Return True if all characters in S are whitespace
    166         and there is at least one character in S, False otherwise.
    167         """
    168         return False
    169 
    170     def istitle(self):  
    171         """
    172         S.istitle() -> bool
    173         
    174         Return True if S is a titlecased string and there is at least one
    175         character in S, i.e. uppercase characters may only follow uncased
    176         characters and lowercase characters only cased ones. Return False
    177         otherwise.
    178         """
    179         return False
    180 
    181     def isupper(self):  
    182         """
    183         S.isupper() -> bool
    184         
    185         Return True if all cased characters in S are uppercase and there is
    186         at least one cased character in S, False otherwise.
    187         """
    188         return False
    189 
    190     def join(self, iterable):  
    191         """ 连接 """
    192         """
    193         S.join(iterable) -> string
    194         
    195         Return a string which is the concatenation of the strings in the
    196         iterable.  The separator between elements is S.
    197         """
    198         return ""
    199 
    200     def ljust(self, width, fillchar=None):  
    201         """ 内容左对齐,右侧填充 """
    202         """
    203         S.ljust(width[, fillchar]) -> string
    204         
    205         Return S left-justified in a string of length width. Padding is
    206         done using the specified fill character (default is a space).
    207         """
    208         return ""
    209 
    210     def lower(self):  
    211         """ 变小写 """
    212         """
    213         S.lower() -> string
    214         
    215         Return a copy of the string S converted to lowercase.
    216         """
    217         return ""
    218 
    219     def lstrip(self, chars=None):  
    220         """ 移除左侧空白 """
    221         """
    222         S.lstrip([chars]) -> string or unicode
    223         
    224         Return a copy of the string S with leading whitespace removed.
    225         If chars is given and not None, remove characters in chars instead.
    226         If chars is unicode, S will be converted to unicode before stripping
    227         """
    228         return ""
    229 
    230     def partition(self, sep):  
    231         """ 分割,前,中,后三部分 """
    232         """
    233         S.partition(sep) -> (head, sep, tail)
    234         
    235         Search for the separator sep in S, and return the part before it,
    236         the separator itself, and the part after it.  If the separator is not
    237         found, return S and two empty strings.
    238         """
    239         pass
    240 
    241     def replace(self, old, new, count=None):  
    242         """ 替换 """
    243         """
    244         S.replace(old, new[, count]) -> string
    245         
    246         Return a copy of string S with all occurrences of substring
    247         old replaced by new.  If the optional argument count is
    248         given, only the first count occurrences are replaced.
    249         """
    250         return ""
    251 
    252     def rfind(self, sub, start=None, end=None):  
    253         """
    254         S.rfind(sub [,start [,end]]) -> int
    255         
    256         Return the highest index in S where substring sub is found,
    257         such that sub is contained within S[start:end].  Optional
    258         arguments start and end are interpreted as in slice notation.
    259         
    260         Return -1 on failure.
    261         """
    262         return 0
    263 
    264     def rindex(self, sub, start=None, end=None):  
    265         """
    266         S.rindex(sub [,start [,end]]) -> int
    267         
    268         Like S.rfind() but raise ValueError when the substring is not found.
    269         """
    270         return 0
    271 
    272     def rjust(self, width, fillchar=None):  
    273         """
    274         S.rjust(width[, fillchar]) -> string
    275         
    276         Return S right-justified in a string of length width. Padding is
    277         done using the specified fill character (default is a space)
    278         """
    279         return ""
    280 
    281     def rpartition(self, sep):  
    282         """
    283         S.rpartition(sep) -> (head, sep, tail)
    284         
    285         Search for the separator sep in S, starting at the end of S, and return
    286         the part before it, the separator itself, and the part after it.  If the
    287         separator is not found, return two empty strings and S.
    288         """
    289         pass
    290 
    291     def rsplit(self, sep=None, maxsplit=None):  
    292         """
    293         S.rsplit([sep [,maxsplit]]) -> list of strings
    294         
    295         Return a list of the words in the string S, using sep as the
    296         delimiter string, starting at the end of the string and working
    297         to the front.  If maxsplit is given, at most maxsplit splits are
    298         done. If sep is not specified or is None, any whitespace string
    299         is a separator.
    300         """
    301         return []
    302 
    303     def rstrip(self, chars=None):  
    304         """
    305         S.rstrip([chars]) -> string or unicode
    306         
    307         Return a copy of the string S with trailing whitespace removed.
    308         If chars is given and not None, remove characters in chars instead.
    309         If chars is unicode, S will be converted to unicode before stripping
    310         """
    311         return ""
    312 
    313     def split(self, sep=None, maxsplit=None):  
    314         """ 分割, maxsplit最多分割几次 """
    315         """
    316         S.split([sep [,maxsplit]]) -> list of strings
    317         
    318         Return a list of the words in the string S, using sep as the
    319         delimiter string.  If maxsplit is given, at most maxsplit
    320         splits are done. If sep is not specified or is None, any
    321         whitespace string is a separator and empty strings are removed
    322         from the result.
    323         """
    324         return []
    325 
    326     def splitlines(self, keepends=False):  
    327         """ 根据换行分割 """
    328         """
    329         S.splitlines(keepends=False) -> list of strings
    330         
    331         Return a list of the lines in S, breaking at line boundaries.
    332         Line breaks are not included in the resulting list unless keepends
    333         is given and true.
    334         """
    335         return []
    336 
    337     def startswith(self, prefix, start=None, end=None):  
    338         """ 是否起始 """
    339         """
    340         S.startswith(prefix[, start[, end]]) -> bool
    341         
    342         Return True if S starts with the specified prefix, False otherwise.
    343         With optional start, test S beginning at that position.
    344         With optional end, stop comparing S at that position.
    345         prefix can also be a tuple of strings to try.
    346         """
    347         return False
    348 
    349     def strip(self, chars=None):  
    350         """ 移除两端空白 """
    351         """
    352         S.strip([chars]) -> string or unicode
    353         
    354         Return a copy of the string S with leading and trailing
    355         whitespace removed.
    356         If chars is given and not None, remove characters in chars instead.
    357         If chars is unicode, S will be converted to unicode before stripping
    358         """
    359         return ""
    360 
    361     def swapcase(self):  
    362         """ 大写变小写,小写变大写 """
    363         """
    364         S.swapcase() -> string
    365         
    366         Return a copy of the string S with uppercase characters
    367         converted to lowercase and vice versa.
    368         """
    369         return ""
    370 
    371     def title(self):  
    372         """
    373         S.title() -> string
    374         
    375         Return a titlecased version of S, i.e. words start with uppercase
    376         characters, all remaining cased characters have lowercase.
    377         """
    378         return ""
    379 
    380     def translate(self, table, deletechars=None):  
    381         """
    382         转换,需要先做一个对应表,最后一个表示删除字符集合
    383         intab = "aeiou"
    384         outtab = "12345"
    385         trantab = maketrans(intab, outtab)
    386         str = "this is string example....wow!!!"
    387         print str.translate(trantab, 'xm')
    388         """
    389 
    390         """
    391         S.translate(table [,deletechars]) -> string
    392         
    393         Return a copy of the string S, where all characters occurring
    394         in the optional argument deletechars are removed, and the
    395         remaining characters have been mapped through the given
    396         translation table, which must be a string of length 256 or None.
    397         If the table argument is None, no translation is applied and
    398         the operation simply removes the characters in deletechars.
    399         """
    400         return ""
    401 
    402     def upper(self):  
    403         """
    404         S.upper() -> string
    405         
    406         Return a copy of the string S converted to uppercase.
    407         """
    408         return ""
    409 
    410     def zfill(self, width):  
    411         """方法返回指定长度的字符串,原字符串右对齐,前面填充0。"""
    412         """
    413         S.zfill(width) -> string
    414         
    415         Pad a numeric string S with zeros on the left, to fill a field
    416         of the specified width.  The string S is never truncated.
    417         """
    418         return ""
    419 
    420     def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown
    421         pass
    422 
    423     def _formatter_parser(self, *args, **kwargs): # real signature unknown
    424         pass
    425 
    426     def __add__(self, y):  
    427         """ x.__add__(y) <==> x+y """
    428         pass
    429 
    430     def __contains__(self, y):  
    431         """ x.__contains__(y) <==> y in x """
    432         pass
    433 
    434     def __eq__(self, y):  
    435         """ x.__eq__(y) <==> x==y """
    436         pass
    437 
    438     def __format__(self, format_spec):  
    439         """
    440         S.__format__(format_spec) -> string
    441         
    442         Return a formatted version of S as described by format_spec.
    443         """
    444         return ""
    445 
    446     def __getattribute__(self, name):  
    447         """ x.__getattribute__('name') <==> x.name """
    448         pass
    449 
    450     def __getitem__(self, y):  
    451         """ x.__getitem__(y) <==> x[y] """
    452         pass
    453 
    454     def __getnewargs__(self, *args, **kwargs): # real signature unknown
    455         pass
    456 
    457     def __getslice__(self, i, j):  
    458         """
    459         x.__getslice__(i, j) <==> x[i:j]
    460                    
    461                    Use of negative indices is not supported.
    462         """
    463         pass
    464 
    465     def __ge__(self, y):  
    466         """ x.__ge__(y) <==> x>=y """
    467         pass
    468 
    469     def __gt__(self, y):  
    470         """ x.__gt__(y) <==> x>y """
    471         pass
    472 
    473     def __hash__(self):  
    474         """ x.__hash__() <==> hash(x) """
    475         pass
    476 
    477     def __init__(self, string=''): # known special case of str.__init__
    478         """
    479         str(object='') -> string
    480         
    481         Return a nice string representation of the object.
    482         If the argument is a string, the return value is the same object.
    483         # (copied from class doc)
    484         """
    485         pass
    486 
    487     def __len__(self):  
    488         """ x.__len__() <==> len(x) """
    489         pass
    490 
    491     def __le__(self, y):  
    492         """ x.__le__(y) <==> x<=y """
    493         pass
    494 
    495     def __lt__(self, y):  
    496         """ x.__lt__(y) <==> x<y """
    497         pass
    498 
    499     def __mod__(self, y):  
    500         """ x.__mod__(y) <==> x%y """
    501         pass
    502 
    503     def __mul__(self, n):  
    504         """ x.__mul__(n) <==> x*n """
    505         pass
    506 
    507     @staticmethod # known case of __new__
    508     def __new__(S, *more):  
    509         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
    510         pass
    511 
    512     def __ne__(self, y):  
    513         """ x.__ne__(y) <==> x!=y """
    514         pass
    515 
    516     def __repr__(self):  
    517         """ x.__repr__() <==> repr(x) """
    518         pass
    519 
    520     def __rmod__(self, y):  
    521         """ x.__rmod__(y) <==> y%x """
    522         pass
    523 
    524     def __rmul__(self, n):  
    525         """ x.__rmul__(n) <==> n*x """
    526         pass
    527 
    528     def __sizeof__(self):  
    529         """ S.__sizeof__() -> size of S in memory, in bytes """
    530         pass
    531 
    532     def __str__(self):  
    533         """ x.__str__() <==> str(x) """
    534         pass
    535 
    536 str
    str

    五、列表

    List是处理和存放一组数据的列表

    如:[11,22,33]、['saneri', 'alex']

    每个列表都具备如下功能:

    List操作包含以下函数:
    cmp(list1, list2):    比较两个列表的元素,两个元素相同返回0,前大后小返回1,前小后大返回-1
    len(list):                列表元素个数
    max(list):              返回列表元素最大值
    min(list):               返回列表元素最小值
    list('var'):               将元素转换为列表
    del L[1]                   删除指定下标的元素
    del L[1:3]                删除指定下标范围的元素

    List操作包含以下方法:
    L.append('var')        append方法用于在列表的尾部追加元素,参数'var'是插入元素的值
    L.insert(index,'var')     用于将对象插入到列表中,俩个参数,第一个是索引位置,第二个插入的元素对象.
    L.pop()            返回列表最后一个元素,并从List中删除.
    Lpop(index)         返回列表索引的元素,并删除.
    L.count(var)          该元素在列表中出现的个数
    L.index('var')         取出元素的位置(下标),无则抛出异常.
    L.remove('var')        remove方法用于从列表中移除第一次的值(值如果有重复则删除第一个)
    L.sort()           排序
    L.reverse()          倒序
    L.extend(list1)        extend方法用于将两个列表合并,将list1列表的值添加到L列表的后面。

    Python列表脚本操作符:

    List 中 + 和 * 的操作符与字符串相似。+ 号用于组合列表,* 号用于重复列表。

    Python列表截取:
    Python的列表截取与字符串操作类型,如下所示:

    L = ['spam', 'Spam', 'SPAM!','xusandu']

    实例:

     1 >>> ShoppingList = ['car','clothers','iphone']                  //定义列表
     2 >>> ShoppingList.append('Alex')                        //在列表中插入'Alex'字符
     3 >>> ShoppingList                                    //查看列表
     4 ['car', 'clothers', 'iphone', 'Alex']
     5 >>> ShoppingList.insert(0,'top')                    //在列表下标为零处(即列表第一个元素),插入‘top’元素
     6 >>> ShoppingList
     7 ['top', 'car', 'clothers', 'iphone', 'Alex']
     8 >>> 
     9 >>> ShoppingList[0]                        //查看下标为零的元素
    10 'top'
    11 >>> ShoppingList[2]                        //查看下标为2的元素
    12 'clothers'
    13 >>> ShoppingList[0] = 'car'                  //将下标为0的元素(即‘top’字符)替换为‘car’  
    14 >>> ShoppingList
    15 ['car', 'car', 'clothers', 'iphone', 'Alex']
    16 >>> ShoppingList.pop()                    //列表最后一个元素(Alex),并从List中删除掉
    17 'Alex'
    18 >>> ShoppingList
    19 ['car', 'car', 'clothers', 'iphone']
    20 >>> 
    21 >>> ShoppingList.remove('iphone')             //从列表中移除'iphone'元素
    22 >>> ShoppingList
    23 ['car', 'car', 'clothers']
    24 >>> 
    25 >>> ShoppingList.append('rain')
    26 >>> ShoppingList.count('car')                //统计列表中元素'car'的个数
    27 2
    28 >>> 'car' in ShoppingList                  //List列表中查找'car'元素,如果存在则返回Ture
    29 True
    30 >>> 
    31 >>> ShoppingList
    32 ['car', 'car', 'clothers', 'rain']
    33 >>> ShoppingList.index('rain')
    34 3
    35 >>> ShoppingList
    36 ['car', 'car', 'clothers', 'rain']
    37 >>> del ShoppingList[0]                //使用del 函数删除List中下标为0的元素.
    38 >>> ShoppingList       
    39 ['car', 'clothers', 'rain']
    40 >>> 

    六、元组(tuple)

    不可变序列-----元组 tuple 
    元组通过圆括号中用逗号分隔的项目定义,不可以添加和删除元组.

    如:(11,22,33)、('saneri', 'alex')

    每个元组都具备如下功能:connt,index

    1 >>> name_tuple = ('a','b','c','a','b')
    2 >>> type(name_tuple)
    3 <type 'tuple'>
    4 >>> name_tuple.count('a')
    5 2
    6 >>> name_tuple.index('b')             //获取b元素下标位置.
    7 1

    七、字典

    字典是Python语言中唯一的映射类型。
    映射类型对象里哈希值(键,key)和指向的对象(值,value)是一对多的的关系,通常被认为是可变的哈希表。
    字典对象是可变的,它是一个容器类型,能存储任意个数的Python对象,其中也可包括其他容器类型。

    技巧:
    字典中包含列表:dict = {"ZhangSan" : ['23','IT'],"Lisi" : ['22','dota']}
    字典中包含字典:dict = {"Wangwu" : {"age" : 23,"job":"IT"},"Song" : {"age":22,"job":"dota"}}

    Dict 操作包含以下方法:
    D = {"ZhangSan" : ['23','IT'],"Lisi" : ['22','dota']}

    D.clear()          清空字典D中的内容
    D.keys()           查看字典所有主键

    D.values()         查看字典所有value内容

    D.popitem()        默认删除第一个键值

    D.has_key('rain')     查询字典中是否有某个键

    D['James'] = '23'     添加新item到字典

    str(D)          输出字典可打印的字符串表示

    del D['rain']      删除item

    cmp(a,b)        首先比较主键长度,然后比较键大小,然后比较键值大小,(第一个大返回1,小返回-1,一样返回0)

    D.fromkeys(seq[, value]))    fromkeys()方法从序列键和值设置为value来创建一个新的字典。实例如下:

     1 seq = ('name', 'age', 'sex')
     2 dict = dict.fromkeys(seq)
     3 print "New Dictionary : %s" %  str(dict)
     4 
     5 dict = dict.fromkeys(seq, 10)
     6 print "New Dictionary : %s" %  str(dict)
     7 
     8 当我们运行上面的程序,它会产生以下结果:
     9 New Dictionary : {'age': None, 'name': None, 'sex': None}
    10 New Dictionary : {'age': 10, 'name': 10, 'sex': 10}
    fromkeys方法

    setdefault()          setdefault() 函数和get()方法类似, 如果键不已经存在于字典中,将会添加键并将值设为默认值。

     1 dict.setdefault(key, default=None)
     2 key -- 查找的键值.
     3  
     4 default -- 键不存在时,设置的默认键值。 
     5 dict = {'Name': 'Zara', 'Age': 7}
     6 
     7 print "Value : %s" %  dict.setdefault('Age', None)
     8 print "Value : %s" %  dict.setdefault('Sex', None)
     9 以上实例输出结果为:
    10 Value : 7
    11 Value : None
    setdefault

    每个字典具备如下功能:

      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
    dict

    八、set集合

    set是一个无序且不重复的元素集合

    a &b 交集
    a | b 并集
    a ^ b 取出非交集的数
    a -b a里面有b里面没有

      1 class set(object):
      2     """
      3     set() -> new empty set object
      4     set(iterable) -> new set object
      5     
      6     Build an unordered collection of unique elements.
      7     """
      8     def add(self, *args, **kwargs): # real signature unknown
      9         """ 添加 """
     10         """
     11         Add an element to a set.
     12         
     13         This has no effect if the element is already present.
     14         """
     15         pass
     16 
     17     def clear(self, *args, **kwargs): # real signature unknown
     18         """ Remove all elements from this set. """
     19         pass
     20 
     21     def copy(self, *args, **kwargs): # real signature unknown
     22         """ Return a shallow copy of a set. """
     23         pass
     24 
     25     def difference(self, *args, **kwargs): # real signature unknown
     26         """
     27         Return the difference of two or more sets as a new set.
     28         
     29         (i.e. all elements that are in this set but not the others.)
     30         """
     31         pass
     32 
     33     def difference_update(self, *args, **kwargs): # real signature unknown
     34         """ 删除当前set中的所有包含在 new set 里的元素 """
     35         """ Remove all elements of another set from this set. """
     36         pass
     37 
     38     def discard(self, *args, **kwargs): # real signature unknown
     39         """ 移除元素 """
     40         """
     41         Remove an element from a set if it is a member.
     42         
     43         If the element is not a member, do nothing.
     44         """
     45         pass
     46 
     47     def intersection(self, *args, **kwargs): # real signature unknown
     48         """ 取交集,新创建一个set """
     49         """
     50         Return the intersection of two or more sets as a new set.
     51         
     52         (i.e. elements that are common to all of the sets.)
     53         """
     54         pass
     55 
     56     def intersection_update(self, *args, **kwargs): # real signature unknown
     57         """ 取交集,修改原来set """
     58         """ Update a set with the intersection of itself and another. """
     59         pass
     60 
     61     def isdisjoint(self, *args, **kwargs): # real signature unknown
     62         """ 如果没有交集,返回true  """
     63         """ Return True if two sets have a null intersection. """
     64         pass
     65 
     66     def issubset(self, *args, **kwargs): # real signature unknown
     67         """ 是否是子集 """
     68         """ Report whether another set contains this set. """
     69         pass
     70 
     71     def issuperset(self, *args, **kwargs): # real signature unknown
     72         """ 是否是父集 """
     73         """ Report whether this set contains another set. """
     74         pass
     75 
     76     def pop(self, *args, **kwargs): # real signature unknown
     77         """ 移除 """
     78         """
     79         Remove and return an arbitrary set element.
     80         Raises KeyError if the set is empty.
     81         """
     82         pass
     83 
     84     def remove(self, *args, **kwargs): # real signature unknown
     85         """ 移除 """
     86         """
     87         Remove an element from a set; it must be a member.
     88         
     89         If the element is not a member, raise a KeyError.
     90         """
     91         pass
     92 
     93     def symmetric_difference(self, *args, **kwargs): # real signature unknown
     94         """ 差集,创建新对象"""
     95         """
     96         Return the symmetric difference of two sets as a new set.
     97         
     98         (i.e. all elements that are in exactly one of the sets.)
     99         """
    100         pass
    101 
    102     def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
    103         """ 差集,改变原来 """
    104         """ Update a set with the symmetric difference of itself and another. """
    105         pass
    106 
    107     def union(self, *args, **kwargs): # real signature unknown
    108         """ 并集 """
    109         """
    110         Return the union of sets as a new set.
    111         
    112         (i.e. all elements that are in either set.)
    113         """
    114         pass
    115 
    116     def update(self, *args, **kwargs): # real signature unknown
    117         """ 更新 """
    118         """ Update a set with the union of itself and others. """
    119         pass
    120 
    121     def __and__(self, y): # real signature unknown; restored from __doc__
    122         """ x.__and__(y) <==> x&y """
    123         pass
    124 
    125     def __cmp__(self, y): # real signature unknown; restored from __doc__
    126         """ x.__cmp__(y) <==> cmp(x,y) """
    127         pass
    128 
    129     def __contains__(self, y): # real signature unknown; restored from __doc__
    130         """ x.__contains__(y) <==> y in x. """
    131         pass
    132 
    133     def __eq__(self, y): # real signature unknown; restored from __doc__
    134         """ x.__eq__(y) <==> x==y """
    135         pass
    136 
    137     def __getattribute__(self, name): # real signature unknown; restored from __doc__
    138         """ x.__getattribute__('name') <==> x.name """
    139         pass
    140 
    141     def __ge__(self, y): # real signature unknown; restored from __doc__
    142         """ x.__ge__(y) <==> x>=y """
    143         pass
    144 
    145     def __gt__(self, y): # real signature unknown; restored from __doc__
    146         """ x.__gt__(y) <==> x>y """
    147         pass
    148 
    149     def __iand__(self, y): # real signature unknown; restored from __doc__
    150         """ x.__iand__(y) <==> x&=y """
    151         pass
    152 
    153     def __init__(self, seq=()): # known special case of set.__init__
    154         """
    155         set() -> new empty set object
    156         set(iterable) -> new set object
    157         
    158         Build an unordered collection of unique elements.
    159         # (copied from class doc)
    160         """
    161         pass
    162 
    163     def __ior__(self, y): # real signature unknown; restored from __doc__
    164         """ x.__ior__(y) <==> x|=y """
    165         pass
    166 
    167     def __isub__(self, y): # real signature unknown; restored from __doc__
    168         """ x.__isub__(y) <==> x-=y """
    169         pass
    170 
    171     def __iter__(self): # real signature unknown; restored from __doc__
    172         """ x.__iter__() <==> iter(x) """
    173         pass
    174 
    175     def __ixor__(self, y): # real signature unknown; restored from __doc__
    176         """ x.__ixor__(y) <==> x^=y """
    177         pass
    178 
    179     def __len__(self): # real signature unknown; restored from __doc__
    180         """ x.__len__() <==> len(x) """
    181         pass
    182 
    183     def __le__(self, y): # real signature unknown; restored from __doc__
    184         """ x.__le__(y) <==> x<=y """
    185         pass
    186 
    187     def __lt__(self, y): # real signature unknown; restored from __doc__
    188         """ x.__lt__(y) <==> x<y """
    189         pass
    190 
    191     @staticmethod # known case of __new__
    192     def __new__(S, *more): # real signature unknown; restored from __doc__
    193         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
    194         pass
    195 
    196     def __ne__(self, y): # real signature unknown; restored from __doc__
    197         """ x.__ne__(y) <==> x!=y """
    198         pass
    199 
    200     def __or__(self, y): # real signature unknown; restored from __doc__
    201         """ x.__or__(y) <==> x|y """
    202         pass
    203 
    204     def __rand__(self, y): # real signature unknown; restored from __doc__
    205         """ x.__rand__(y) <==> y&x """
    206         pass
    207 
    208     def __reduce__(self, *args, **kwargs): # real signature unknown
    209         """ Return state information for pickling. """
    210         pass
    211 
    212     def __repr__(self): # real signature unknown; restored from __doc__
    213         """ x.__repr__() <==> repr(x) """
    214         pass
    215 
    216     def __ror__(self, y): # real signature unknown; restored from __doc__
    217         """ x.__ror__(y) <==> y|x """
    218         pass
    219 
    220     def __rsub__(self, y): # real signature unknown; restored from __doc__
    221         """ x.__rsub__(y) <==> y-x """
    222         pass
    223 
    224     def __rxor__(self, y): # real signature unknown; restored from __doc__
    225         """ x.__rxor__(y) <==> y^x """
    226         pass
    227 
    228     def __sizeof__(self): # real signature unknown; restored from __doc__
    229         """ S.__sizeof__() -> size of S in memory, in bytes """
    230         pass
    231 
    232     def __sub__(self, y): # real signature unknown; restored from __doc__
    233         """ x.__sub__(y) <==> x-y """
    234         pass
    235 
    236     def __xor__(self, y): # real signature unknown; restored from __doc__
    237         """ x.__xor__(y) <==> x^y """
    238         pass
    239 
    240     __hash__ = None
    241 复制代码
    set
    1 L.set()
    2 >>> txt1 = [1,2,3,4,5]
    3 >>> txt2 = [2,4,6,7]
    4 >>> txt3 = list(set(txt1 + txt2))
    5 >>> 
    6 >>> print txt3
    7 [1, 2, 3, 4, 5, 6, 7]
    8 >>> 

    九、collection系列:

    1、计数器(counter)

    Counter是对字典类型的补充,用于追踪值的出现次数。

    具备字典的所有功能 + 自己的功能:

    1 c = Counter('abcdeabcdabcaba')
    2 print c
    3 输出:Counter({'a': 5, 'b': 4, 'c': 3, 'd': 2, 'e': 1})

    2、有序字典(orderedDict )

    orderdDict是对字典类型的补充,他记住了字典元素添加的顺序

    3、默认字典(defaultdict) defaultdict是对字典的类型的补充,他默认给字典的值设置了一个类型。

    需求:

    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}defaultdict字典解决方法
     1 values = [11, 22, 33,44,55,66,77,88,99,90]
     2 
     3 my_dict = {}
     4 
     5 for value in  values:
     6     if value>66:
     7         if my_dict.has_key('k1'):
     8             my_dict['k1'].append(value)
     9         else:
    10             my_dict['k1'] = [value]
    11     else:
    12         if my_dict.has_key('k2'):
    13             my_dict['k2'].append(value)
    14         else:
    15             my_dict['k2'] = [value]
    原生字典解决方法
     1 from collections import defaultdict
     2 
     3 values = [11, 22, 33,44,55,66,77,88,99,90]
     4 
     5 my_dict = defaultdict(list)
     6 
     7 for value in  values:
     8     if value>66:
     9         my_dict['k1'].append(value)
    10     else:
    11         my_dict['k2'].append(value)
    defaultdict字典解决方法

    4、可命名元组(namedtuple)

    根据nametuple可以创建一个包含tuple所有功能以及其他功能的类型.

    1 import collections
    2 Mytuple = collections.namedtuple('Mytuple',['x','y','z'])
    3 new = Mytuple(1,2,3)
    4 print new
    5 Mytuple(x=1, y=2, z=3)

    5、双向队列(deque)

     两边都可以存取,线程安全的)   在collection模块中

      单向队列:先进先出(FIFO)
      栈:弹夹(后进的先出) 再Queue模块中

    1 >>> import Queue
    2         >>> Q = Queue.Queue(10)           最多插入10个数
    3         >>> Q.put(1)                          向队列中添加值
    4         >>> Q.put(2)
    5         >>> Q.put(3)
    6         >>> Q.put(4)        
    7         Q.get()        

    一、迭代器

    对于Python 列表的 for 循环,他的内部原理:查看下一个元素是否存在,如果存在,则取出,如果不存在,则报异常 StopIteration。(python内部对异常已处理)

    listiterator

    二、生成器

    range不是生成器 而 xrange 是生成器

    readlines不是生成器 而 xreadlines 是生成器

    1 >>> print range(10)
    2 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    3 >>> print xrange(10)
    4 xrange(10)

    生成器内部基于yield创建,即:对于生成器只有使用时才创建,从而不避免内存浪费

    练习:有如下列表:
        [13, 22, 6, 99, 11]
     
    请按照一下规则计算:
    1322 比较,将大的值放在右侧,即:[13, 22, 6, 99, 11]
    226 比较,将大的值放在右侧,即:[13, 6, 22, 99, 11]
    2299 比较,将大的值放在右侧,即:[13, 6, 22, 99, 11]
    9942 比较,将大的值放在右侧,即:[13, 6, 22, 11, 99,]
     
    136 比较,将大的值放在右侧,即:[6, 13, 22, 11, 99,]
    ...

    解析:
    li = [13, 22, 6, 99, 11]
    
    for m in range(len(li)-1):
    
        for n in range(m+1, len(li)):
            if li[m]> li[n]:
                temp = li[n]
                li[n] = li[m]
                li[m] = temp
    
    print li
     

    让a和b的值互换位置:

     1 >>> a = 123
     2 >>> b = 321
     3 >>> a,b
     4 (123, 321)
     5 >>> temp = a
     6 >>> temp
     7 123
     8 >>> a = b
     9 >>> a
    10 321
    11 >>> b = temp
    12 >>> a,b
    13 (321, 123)
    14 >>>
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  • 原文地址:https://www.cnblogs.com/saneri/p/4958646.html
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