Python基础之【第二篇】

摘要:
在字典查找中,哈希值用于快速比较字典关键字。如果这两个值相等,则哈希值也相等。

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

Python基础之【第二篇】第1张

 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.
Python基础之【第二篇】第2张Python基础之【第二篇】第3张
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:

Python基础之【第二篇】第2张Python基础之【第二篇】第5张
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:

Python基础之【第二篇】第2张Python基础之【第二篇】第7张
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:  

Python基础之【第二篇】第2张Python基础之【第二篇】第9张
  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基础之【第二篇】第10张

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']

Python基础之【第二篇】第11张

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:

Python基础之【第二篇】第2张Python基础之【第二篇】第13张
 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。

Python基础之【第二篇】第2张Python基础之【第二篇】第15张
 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:

Python基础之【第二篇】第2张Python基础之【第二篇】第17张
  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

Python基础之【第二篇】第2张Python基础之【第二篇】第19张
  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
Python基础之【第二篇】第2张Python基础之【第二篇】第21张
 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
Python基础之【第二篇】第2张Python基础之【第二篇】第23张
 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()        

Python基础之【第二篇】第24张

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)

Python基础之【第二篇】第2张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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