python之数据类型1

什么是数据类型及数据类型分类

       python中的数据类型

python使用对象模型来存储数据，每一个数据类型都有一个内置的类，每新建一个数据，实际就是在初始化生成一个对象，即所有数据都是对象
对象三个特性

• 身份：内存地址，可以用id()获取
• 类型：决定了该对象可以保存什么类型值，可执行何种操作，需遵循什么规则，可用type()获取
• 值：对象保存的真实数据

注：我们在定义数据类型，只需这样：x＝1，内部生成1这一内存对象会自动触发，我们无需关心

这里的字符串、数字、列表等都是数据类型（用来描述某种状态或者特性）除此之外还有很多其他数据，处理不同的数据就需要定义不同的数据类型

标准类型	其他类型
数字	类型type
字符串	Null
列表	文件
元组	集合
字典	函数／方法
	类
	模块

  2 标准数据类型

   定义

特性

1.只能存放一个值

2.一经定义，不可更改

3.直接访问

分类：整型，长整型，布尔，浮点，复数

整型：Python的整型相当于C中的long型,Python中的整数可以用十进制,八进制,十六进制表示。

>>> 10
10         --------->默认十进制
>>> oct(10)
'012'      --------->八进制表示整数时，数值前面要加上一个前缀“0”
>>> hex(10)
'0xa'      --------->十六进制表示整数时，数字前面要加上前缀0X或0x

python2.*与python3.*关于整型的区别

python2.*
在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647

在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
python3.*整形长度无限制 

长整型：python2.*，跟C语言不同，Python的长整型没有指定位宽，也就是说Python没有限制长整型数值的大小，
但是实际上由于机器内存有限，所以我们使用的长整型数值不可能无限大。
在使用过程中，我们如何区分长整型和整型数值呢？
通常的做法是在数字尾部加上一个大写字母L或小写字母l以表示该整数是长整型的，例如：
a = 9223372036854775808L
注意，自从Python2起，如果发生溢出，Python会自动将整型数据转换为长整型，
所以如今在长整型数据后面不加字母L也不会导致严重后果了。

python3.*，长整型，整型统一归为整型

复数：复数由实数部分和虚数部分组成，一般形式为x＋yj，其中的x是复数的实数部分，y是复数的虚数部分，这里的x和y都是实数。

注意，虚数部分的字母j大小写都可以，如下：>>> 1.3 + 2.5j == 1.3 + 2.5J 
                                       True
        浮点数float：Python的浮点数就是数学中的小数，类似C语言中的double。
在运算中，整数与浮点数运算的结果是浮点数
浮点数也就是小数，之所以称为浮点数，是因为按照科学记数法表示时，
一个浮点数的小数点位置是可变的，比如，1.23*109和12.3*108是相等的。
浮点数可以用数学写法，如1.23，3.14，-9.01，等等。但是对于很大或很小的浮点数，
就必须用科学计数法表示，把10用e替代，1.23*109就是1.23e9，或者12.3e8，0.000012
可以写成1.2e-5，等等。
整数和浮点数在计算机内部存储的方式是不同的，整数运算永远是精确的而浮点数运算则可能会有
四舍五入的误差。                                   
3 字符串定义：它是一个有序的字符的集合，用于存储和表示基本的文本信息，‘’或“”或‘’‘ ’‘’中间包含的内容称之为字符串
  特性：
      1.只能存放一个值
      2.不可变
      3.按照从左到右的顺序定义字符集合，下标从0开始顺序访问，有序
  补充：
　　1.字符串的单引号和双引号都无法取消特殊字符的含义，如果想让引号内所有字符均取消特殊意义，在引号前面加r，如name＝r'l\thf'
　　2.unicode字符串与r连用必需在r前面，如name＝ur'l\thf'
相关的工厂函数：

整型工厂函数python2.*

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)
    """
    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()
        """
        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)
        # (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

整型工厂函数python3.*

class int(object):
    """
    int(x=0) -> integer
    int(x, base=10) -> integer

    Convert a number or string to an integer, or return 0 if no arguments
    are given.  If x is a number, return x.__int__().  For floating point
    numbers, this truncates towards zero.

    If x is not a number or if base is given, then x must be a string,
    bytes, or bytearray instance 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)
    """
    def bit_length(self): # real signature unknown; restored from __doc__
        """ 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()
        """
        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

    @classmethod # known case
    def from_bytes(cls, bytes, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__
        """
        int.from_bytes(bytes, byteorder, *, signed=False) -> int

        Return the integer represented by the given array of bytes.

        The bytes argument must be a bytes-like object (e.g. bytes or bytearray).

        The byteorder argument determines the byte order used to represent the
        integer.  If byteorder is 'big', the most significant byte is at the
        beginning of the byte array.  If byteorder is 'little', the most
        significant byte is at the end of the byte array.  To request the native
        byte order of the host system, use `sys.byteorder' as the byte order value.

        The signed keyword-only argument indicates whether two's complement is
        used to represent the integer.
        """
        pass

    def to_bytes(self, length, byteorder, *args, **kwargs): # real signature unknown; NOTE: unreliably restored from __doc__
        """
        int.to_bytes(length, byteorder, *, signed=False) -> bytes

        Return an array of bytes representing an integer.

        The integer is represented using length bytes.  An OverflowError is
        raised if the integer is not representable with the given number of
        bytes.

        The byteorder argument determines the byte order used to represent the
        integer.  If byteorder is 'big', the most significant byte is at the
        beginning of the byte array.  If byteorder is 'little', the most
        significant byte is at the end of the byte array.  To request the native
        byte order of the host system, use `sys.byteorder' as the byte order value.

        The signed keyword-only argument determines whether two's complement is
        used to represent the integer.  If signed is False and a negative integer
        is given, an OverflowError is raised.
        """
        pass

    def __abs__(self, *args, **kwargs): # real signature unknown
        """ abs(self) """
        pass

    def __add__(self, *args, **kwargs): # real signature unknown
        """ Return self+value. """
        pass

    def __and__(self, *args, **kwargs): # real signature unknown
        """ Return self&value. """
        pass

    def __bool__(self, *args, **kwargs): # real signature unknown
        """ self != 0 """
        pass

    def __ceil__(self, *args, **kwargs): # real signature unknown
        """
        整数返回自己
        如果是小数
         math.ceil(3.1)返回4
        """
        """ Ceiling of an Integral returns itself. """
        pass

    def __divmod__(self, *args, **kwargs): # real signature unknown
        """ 相除，得到商和余数组成的元组 """
        """ Return divmod(self, value). """
        pass

    def __eq__(self, *args, **kwargs): # real signature unknown
        """ Return self==value. """
        pass

    def __float__(self, *args, **kwargs): # real signature unknown
        """ float(self) """
        pass

    def __floordiv__(self, *args, **kwargs): # real signature unknown
        """ Return self//value. """
        pass

    def __floor__(self, *args, **kwargs): # real signature unknown
        """ Flooring an Integral returns itself. """
        pass

    def __format__(self, *args, **kwargs): # real signature unknown
        pass

    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __getnewargs__(self, *args, **kwargs): # real signature unknown
        pass

    def __ge__(self, *args, **kwargs): # real signature unknown
        """ Return self>=value. """
        pass

    def __gt__(self, *args, **kwargs): # real signature unknown
        """ Return self>value. """
        pass

    def __hash__(self, *args, **kwargs): # real signature unknown
        """ Return hash(self). """
        pass

    def __index__(self, *args, **kwargs): # real signature unknown
        """ 用于切片，数字无意义 """
        """ Return self converted to an integer, if self is suitable for use as an index into a list. """
        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) -> integer
        int(x, base=10) -> integer

        Convert a number or string to an integer, or return 0 if no arguments
        are given.  If x is a number, return x.__int__().  For floating point
        numbers, this truncates towards zero.

        If x is not a number or if base is given, then x must be a string,
        bytes, or bytearray instance 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)
        # (copied from class doc)
        """
        pass

    def __int__(self, *args, **kwargs): # real signature unknown

        """ int(self) """
        pass

    def __invert__(self, *args, **kwargs): # real signature unknown
        """ ~self """
        pass

    def __le__(self, *args, **kwargs): # real signature unknown
        """ Return self<=value. """
        pass

    def __lshift__(self, *args, **kwargs): # real signature unknown
        """ Return self<<value. """
        pass

    def __lt__(self, *args, **kwargs): # real signature unknown
        """ Return self<value. """
        pass

    def __mod__(self, *args, **kwargs): # real signature unknown
        """ Return self%value. """
        pass

    def __mul__(self, *args, **kwargs): # real signature unknown
        """ Return self*value. """
        pass

    def __neg__(self, *args, **kwargs): # real signature unknown
        """ -self """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __ne__(self, *args, **kwargs): # real signature unknown
        """ Return self!=value. """
        pass

    def __or__(self, *args, **kwargs): # real signature unknown
        """ Return self|value. """
        pass

    def __pos__(self, *args, **kwargs): # real signature unknown
        """ +self """
        pass

    def __pow__(self, *args, **kwargs): # real signature unknown
        """ Return pow(self, value, mod). """
        pass

    def __radd__(self, *args, **kwargs): # real signature unknown
        """ Return value+self. """
        pass

    def __rand__(self, *args, **kwargs): # real signature unknown
        """ Return value&self. """
        pass

    def __rdivmod__(self, *args, **kwargs): # real signature unknown
        """ Return divmod(value, self). """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    def __rfloordiv__(self, *args, **kwargs): # real signature unknown
        """ Return value//self. """
        pass

    def __rlshift__(self, *args, **kwargs): # real signature unknown
        """ Return value<<self. """
        pass

    def __rmod__(self, *args, **kwargs): # real signature unknown
        """ Return value%self. """
        pass

    def __rmul__(self, *args, **kwargs): # real signature unknown
        """ Return value*self. """
        pass

    def __ror__(self, *args, **kwargs): # real signature unknown
        """ Return value|self. """
        pass

    def __round__(self, *args, **kwargs): # real signature unknown
        """
        Rounding an Integral returns itself.
        Rounding with an ndigits argument also returns an integer.
        """
        pass

    def __rpow__(self, *args, **kwargs): # real signature unknown
        """ Return pow(value, self, mod). """
        pass

    def __rrshift__(self, *args, **kwargs): # real signature unknown
        """ Return value>>self. """
        pass

    def __rshift__(self, *args, **kwargs): # real signature unknown
        """ Return self>>value. """
        pass

    def __rsub__(self, *args, **kwargs): # real signature unknown
        """ Return value-self. """
        pass

    def __rtruediv__(self, *args, **kwargs): # real signature unknown
        """ Return value/self. """
        pass

    def __rxor__(self, *args, **kwargs): # real signature unknown
        """ Return value^self. """
        pass

    def __sizeof__(self, *args, **kwargs): # real signature unknown
        """ Returns size in memory, in bytes """
        pass

    def __str__(self, *args, **kwargs): # real signature unknown
        """ Return str(self). """
        pass

    def __sub__(self, *args, **kwargs): # real signature unknown
        """ Return self-value. """
        pass

    def __truediv__(self, *args, **kwargs): # real signature unknown
        """ Return self/value. """
        pass

    def __trunc__(self, *args, **kwargs): # real signature unknown
        """ Truncating an Integral returns itself. """
        pass

    def __xor__(self, *args, **kwargs): # real signature unknown
        """ Return self^value. """
        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"""

字符串工厂函数

class str(object):
    """
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str

    Create a new string object from the given object. If encoding or
    errors is specified, then the object must expose a data buffer
    that will be decoded using the given encoding and error handler.
    Otherwise, returns the result of object.__str__() (if defined)
    or repr(object).
    encoding defaults to sys.getdefaultencoding().
    errors defaults to 'strict'.
    """
    def capitalize(self): # real signature unknown; restored from __doc__
        """
        首字母变大写
        S.capitalize() -> str

        Return a capitalized version of S, i.e. make the first character
        have upper case and the rest lower case.
        """
        return ""

    def casefold(self): # real signature unknown; restored from __doc__
        """
        S.casefold() -> str

        Return a version of S suitable for caseless comparisons.
        """
        return ""

    def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        原来字符居中，不够用空格补全
        S.center(width[, fillchar]) -> str

        Return S centered in a string of length width. Padding is
        done using the specified fill character (default is a space)
        """
        return ""

    def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
         从一个范围内的统计某str出现次数
        S.count(sub[, start[, end]]) -> int

        Return the number of non-overlapping occurrences of substring sub in
        string S[start:end].  Optional arguments start and end are
        interpreted as in slice notation.
        """
        return 0

    def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__
        """
        encode(encoding='utf-8',errors='strict')
        以encoding指定编码格式编码，如果出错默认报一个ValueError，除非errors指定的是
        ignore或replace

        S.encode(encoding='utf-8', errors='strict') -> bytes

        Encode S using the codec registered for encoding. Default encoding
        is 'utf-8'. errors may be given to set a different error
        handling scheme. Default is 'strict' meaning that encoding errors raise
        a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
        'xmlcharrefreplace' as well as any other name registered with
        codecs.register_error that can handle UnicodeEncodeErrors.
        """
        return b""

    def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.endswith(suffix[, start[, end]]) -> bool

        Return True if S ends with the specified suffix, False otherwise.
        With optional start, test S beginning at that position.
        With optional end, stop comparing S at that position.
        suffix can also be a tuple of strings to try.
        """
        return False

    def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__
        """
        将字符串中包含的\t转换成tabsize个空格
        S.expandtabs(tabsize=8) -> str

        Return a copy of S where all tab characters are expanded using spaces.
        If tabsize is not given, a tab size of 8 characters is assumed.
        """
        return ""

    def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.find(sub[, start[, end]]) -> int

        Return the lowest index in S where substring sub is found,
        such that sub is contained within S[start:end].  Optional
        arguments start and end are interpreted as in slice notation.

        Return -1 on failure.
        """
        return 0

    def format(self, *args, **kwargs): # known special case of str.format
        """
        格式化输出
        三种形式：
        形式一.
        >>> print('{0}{1}{0}'.format('a','b'))
        aba

        形式二：（必须一一对应）
        >>> print('{}{}{}'.format('a','b'))
        Traceback (most recent call last):
          File "<input>", line 1, in <module>
        IndexError: tuple index out of range
        >>> print('{}{}'.format('a','b'))
        ab

        形式三：
        >>> print('{name} {age}'.format(age=12,name='lhf'))
        lhf 12

        S.format(*args, **kwargs) -> str

        Return a formatted version of S, using substitutions from args and kwargs.
        The substitutions are identified by braces ('{' and '}').
        """
        pass

    def format_map(self, mapping): # real signature unknown; restored from __doc__
        """
        与format区别
        '{name}'.format(**dict(name='alex'))
        '{name}'.format_map(dict(name='alex'))

        S.format_map(mapping) -> str

        Return a formatted version of S, using substitutions from mapping.
        The substitutions are identified by braces ('{' and '}').
        """
        return ""

    def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.index(sub[, start[, end]]) -> int

        Like S.find() but raise ValueError when the substring is not found.
        """
        return 0

    def isalnum(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是字母或数字才返回True

        S.isalnum() -> bool

        Return True if all characters in S are alphanumeric
        and there is at least one character in S, False otherwise.
        """
        return False

    def isalpha(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是字母才返回True
        S.isalpha() -> bool

        Return True if all characters in S are alphabetic
        and there is at least one character in S, False otherwise.
        """
        return False

    def isdecimal(self): # real signature unknown; restored from __doc__
        """
        S.isdecimal() -> bool

        Return True if there are only decimal characters in S,
        False otherwise.
        """
        return False

    def isdigit(self): # real signature unknown; restored from __doc__
        """
        S.isdigit() -> bool

        Return True if all characters in S are digits
        and there is at least one character in S, False otherwise.
        """
        return False

    def isidentifier(self): # real signature unknown; restored from __doc__
        """
        字符串为关键字返回True

        S.isidentifier() -> bool

        Return True if S is a valid identifier according
        to the language definition.

        Use keyword.iskeyword() to test for reserved identifiers
        such as "def" and "class".
        """
        return False

    def islower(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是小写字母才返回True
        S.islower() -> bool

        Return True if all cased characters in S are lowercase and there is
        at least one cased character in S, False otherwise.
        """
        return False

    def isnumeric(self): # real signature unknown; restored from __doc__
        """
        S.isnumeric() -> bool

        Return True if there are only numeric characters in S,
        False otherwise.
        """
        return False

    def isprintable(self): # real signature unknown; restored from __doc__
        """
        S.isprintable() -> bool

        Return True if all characters in S are considered
        printable in repr() or S is empty, False otherwise.
        """
        return False

    def isspace(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是空格才返回True
        S.isspace() -> bool

        Return True if all characters in S are whitespace
        and there is at least one character in S, False otherwise.
        """
        return False

    def istitle(self): # real signature unknown; restored from __doc__
        """
        >>> a='Hello'
        >>> a.istitle()
        True
        >>> a='HellP'
        >>> a.istitle()
        False

        S.istitle() -> bool

        Return True if S is a titlecased string and there is at least one
        character in S, i.e. upper- and titlecase characters may only
        follow uncased characters and lowercase characters only cased ones.
        Return False otherwise.
        """
        return False

    def isupper(self): # real signature unknown; restored from __doc__
        """
        S.isupper() -> bool

        Return True if all cased characters in S are uppercase and there is
        at least one cased character in S, False otherwise.
        """
        return False

    def join(self, iterable): # real signature unknown; restored from __doc__
        """
        #对序列进行操作（分别使用' '与':'作为分隔符）
        >>> seq1 = ['hello','good','boy','doiido']
        >>> print ' '.join(seq1)
        hello good boy doiido
        >>> print ':'.join(seq1)
        hello:good:boy:doiido

        #对字符串进行操作

        >>> seq2 = "hello good boy doiido"
        >>> print ':'.join(seq2)
        h:e:l:l:o: :g:o:o:d: :b:o:y: :d:o:i:i:d:o

        #对元组进行操作

        >>> seq3 = ('hello','good','boy','doiido')
        >>> print ':'.join(seq3)
        hello:good:boy:doiido

        #对字典进行操作

        >>> seq4 = {'hello':1,'good':2,'boy':3,'doiido':4}
        >>> print ':'.join(seq4)
        boy:good:doiido:hello

        #合并目录

        >>> import os
        >>> os.path.join('/hello/','good/boy/','doiido')
        '/hello/good/boy/doiido'

        S.join(iterable) -> str

        Return a string which is the concatenation of the strings in the
        iterable.  The separator between elements is S.
        """
        return ""

    def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        S.ljust(width[, fillchar]) -> str

        Return S left-justified in a Unicode string of length width. Padding is
        done using the specified fill character (default is a space).
        """
        return ""

    def lower(self): # real signature unknown; restored from __doc__
        """
        S.lower() -> str

        Return a copy of the string S converted to lowercase.
        """
        return ""

    def lstrip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.lstrip([chars]) -> str

        Return a copy of the string S with leading whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def maketrans(self, *args, **kwargs): # real signature unknown
        """
        Return a translation table usable for str.translate().

        If there is only one argument, it must be a dictionary mapping Unicode
        ordinals (integers) or characters to Unicode ordinals, strings or None.
        Character keys will be then converted to ordinals.
        If there are two arguments, they must be strings of equal length, and
        in the resulting dictionary, each character in x will be mapped to the
        character at the same position in y. If there is a third argument, it
        must be a string, whose characters will be mapped to None in the result.
        """
        pass

    def partition(self, sep): # real signature unknown; restored from __doc__
        """
        以sep为分割，将S分成head,sep,tail三部分

        S.partition(sep) -> (head, sep, tail)

        Search for the separator sep in S, and return the part before it,
        the separator itself, and the part after it.  If the separator is not
        found, return S and two empty strings.
        """
        pass

    def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
        """
        S.replace(old, new[, count]) -> str

        Return a copy of S with all occurrences of substring
        old replaced by new.  If the optional argument count is
        given, only the first count occurrences are replaced.
        """
        return ""

    def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.rfind(sub[, start[, end]]) -> int

        Return the highest index in S where substring sub is found,
        such that sub is contained within S[start:end].  Optional
        arguments start and end are interpreted as in slice notation.

        Return -1 on failure.
        """
        return 0

    def rindex(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.rindex(sub[, start[, end]]) -> int

        Like S.rfind() but raise ValueError when the substring is not found.
        """
        return 0

    def rjust(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        S.rjust(width[, fillchar]) -> str

        Return S right-justified in a string of length width. Padding is
        done using the specified fill character (default is a space).
        """
        return ""

    def rpartition(self, sep): # real signature unknown; restored from __doc__
        """
        S.rpartition(sep) -> (head, sep, tail)

        Search for the separator sep in S, starting at the end of S, and return
        the part before it, the separator itself, and the part after it.  If the
        separator is not found, return two empty strings and S.
        """
        pass

    def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
        """
        S.rsplit(sep=None, maxsplit=-1) -> list of strings

        Return a list of the words in S, using sep as the
        delimiter string, starting at the end of the string and
        working to the front.  If maxsplit is given, at most maxsplit
        splits are done. If sep is not specified, any whitespace string
        is a separator.
        """
        return []

    def rstrip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.rstrip([chars]) -> str

        Return a copy of the string S with trailing whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
        """
        以sep为分割，将S切分成列表，与partition的区别在于切分结果不包含sep，
        如果一个字符串中包含多个sep那么maxsplit为最多切分成几部分
        >>> a='a,b c\nd\te'
        >>> a.split()
        ['a,b', 'c', 'd', 'e']
        S.split(sep=None, maxsplit=-1) -> list of strings

        Return a list of the words in S, using sep as the
        delimiter string.  If maxsplit is given, at most maxsplit
        splits are done. If sep is not specified or is None, any
        whitespace string is a separator and empty strings are
        removed from the result.
        """
        return []

    def splitlines(self, keepends=None): # real signature unknown; restored from __doc__
        """
        Python splitlines() 按照行('\r', '\r\n', \n')分隔，
        返回一个包含各行作为元素的列表，如果参数 keepends 为 False，不包含换行符，如        果为 True，则保留换行符。
        >>> x
        'adsfasdf\nsadf\nasdf\nadf'
        >>> x.splitlines()
        ['adsfasdf', 'sadf', 'asdf', 'adf']
        >>> x.splitlines(True)
        ['adsfasdf\n', 'sadf\n', 'asdf\n', 'adf']

        S.splitlines([keepends]) -> list of strings

        Return a list of the lines in S, breaking at line boundaries.
        Line breaks are not included in the resulting list unless keepends
        is given and true.
        """
        return []

    def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.startswith(prefix[, start[, end]]) -> bool

        Return True if S starts with the specified prefix, False otherwise.
        With optional start, test S beginning at that position.
        With optional end, stop comparing S at that position.
        prefix can also be a tuple of strings to try.
        """
        return False

    def strip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.strip([chars]) -> str

        Return a copy of the string S with leading and trailing
        whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def swapcase(self): # real signature unknown; restored from __doc__
        """
        大小写反转
        S.swapcase() -> str

        Return a copy of S with uppercase characters converted to lowercase
        and vice versa.
        """
        return ""

    def title(self): # real signature unknown; restored from __doc__
        """
        S.title() -> str

        Return a titlecased version of S, i.e. words start with title case
        characters, all remaining cased characters have lower case.
        """
        return ""

    def translate(self, table): # real signature unknown; restored from __doc__
        """
        table=str.maketrans('alex','big SB')

        a='hello abc'
        print(a.translate(table))

        S.translate(table) -> str

        Return a copy of the string S in which each character has been mapped
        through the given translation table. The table must implement
        lookup/indexing via __getitem__, for instance a dictionary or list,
        mapping Unicode ordinals to Unicode ordinals, strings, or None. If
        this operation raises LookupError, the character is left untouched.
        Characters mapped to None are deleted.
        """
        return ""

    def upper(self): # real signature unknown; restored from __doc__
        """
        S.upper() -> str

        Return a copy of S converted to uppercase.
        """
        return ""

    def zfill(self, width): # real signature unknown; restored from __doc__
        """
        原来字符右对齐，不够用0补齐

        S.zfill(width) -> str

        Pad a numeric string S with zeros on the left, to fill a field
        of the specified width. The string S is never truncated.
        """
        return ""

    def __add__(self, *args, **kwargs): # real signature unknown
        """ Return self+value. """
        pass

    def __contains__(self, *args, **kwargs): # real signature unknown
        """ Return key in self. """
        pass

    def __eq__(self, *args, **kwargs): # real signature unknown
        """ Return self==value. """
        pass

    def __format__(self, format_spec): # real signature unknown; restored from __doc__
        """
        S.__format__(format_spec) -> str

        Return a formatted version of S as described by format_spec.
        """
        return ""

    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __getitem__(self, *args, **kwargs): # real signature unknown
        """ Return self[key]. """
        pass

    def __getnewargs__(self, *args, **kwargs): # real signature unknown
        pass

    def __ge__(self, *args, **kwargs): # real signature unknown
        """ Return self>=value. """
        pass

    def __gt__(self, *args, **kwargs): # real signature unknown
        """ Return self>value. """
        pass

    def __hash__(self, *args, **kwargs): # real signature unknown
        """ Return hash(self). """
        pass

    def __init__(self, value='', encoding=None, errors='strict'): # known special case of str.__init__
        """
        str(object='') -> str
        str(bytes_or_buffer[, encoding[, errors]]) -> str

        Create a new string object from the given object. If encoding or
        errors is specified, then the object must expose a data buffer
        that will be decoded using the given encoding and error handler.
        Otherwise, returns the result of object.__str__() (if defined)
        or repr(object).
        encoding defaults to sys.getdefaultencoding().
        errors defaults to 'strict'.
        # (copied from class doc)
        """
        pass

    def __iter__(self, *args, **kwargs): # real signature unknown
        """ Implement iter(self). """
        pass

    def __len__(self, *args, **kwargs): # real signature unknown
        """ Return len(self). """
        pass

    def __le__(self, *args, **kwargs): # real signature unknown
        """ Return self<=value. """
        pass

    def __lt__(self, *args, **kwargs): # real signature unknown
        """ Return self<value. """
        pass

    def __mod__(self, *args, **kwargs): # real signature unknown
        """ Return self%value. """
        pass

    def __mul__(self, *args, **kwargs): # real signature unknown
        """ Return self*value.n """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __ne__(self, *args, **kwargs): # real signature unknown
        """ Return self!=value. """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    def __rmod__(self, *args, **kwargs): # real signature unknown
        """ Return value%self. """
        pass

    def __rmul__(self, *args, **kwargs): # real signature unknown
        """ Return self*value. """
        pass

    def __sizeof__(self): # real signature unknown; restored from __doc__
        """ S.__sizeof__() -> size of S in memory, in bytes """
        pass

    def __str__(self, *args, **kwargs): # real signature unknown
        """ Return str(self). """
        pass

python中str函数isdigit、isdecimal、isnumeric的区别：

python中str函数isdigit、isdecimal、isnumeric的区别

num = ""  #unicode
num.isdigit()   # True
num.isdecimal() # True
num.isnumeric() # True

num = "" # 全角
num.isdigit()   # True
num.isdecimal() # True
num.isnumeric() # True

num = b"" # byte
num.isdigit()   # True
num.isdecimal() # AttributeError 'bytes' object has no attribute 'isdecimal'
num.isnumeric() # AttributeError 'bytes' object has no attribute 'isnumeric'

num = "IV" # 罗马数字
num.isdigit()   # True
num.isdecimal() # False
num.isnumeric() # True

num = "四" # 汉字
num.isdigit()   # False
num.isdecimal() # False
num.isnumeric() # True

===================
isdigit()
True: Unicode数字，byte数字（单字节），全角数字（双字节），罗马数字
False: 汉字数字
Error: 无

isdecimal()
True: Unicode数字，，全角数字（双字节）
False: 罗马数字，汉字数字
Error: byte数字（单字节）

isnumeric()
True: Unicode数字，全角数字（双字节），罗马数字，汉字数字
False: 无
Error: byte数字（单字节）

================
import unicodedata

unicodedata.digit("")   #
unicodedata.decimal("") #
unicodedata.numeric("") # 2.0

unicodedata.digit("")   #
unicodedata.decimal("") #
unicodedata.numeric("") # 2.0

unicodedata.digit(b"")   # TypeError: must be str, not bytes
unicodedata.decimal(b"") # TypeError: must be str, not bytes
unicodedata.numeric(b"") # TypeError: must be str, not bytes

unicodedata.digit("Ⅷ")   # ValueError: not a digit
unicodedata.decimal("Ⅷ") # ValueError: not a decimal
unicodedata.numeric("Ⅷ") # 8.0

unicodedata.digit("四")   # ValueError: not a digit
unicodedata.decimal("四") # ValueError: not a decimal
unicodedata.numeric("四") # 4.0

#"〇","零","一","壱","二","弐","三","参","四","五","六","七","八","九","十","廿","卅","卌","百","千","万","万","亿"

取值分类

1 可变不可变

可变：列表。字典

不可变：数字，字符串，元组

2 存放值的个数

一个值：数字，字符串

多个值（容器类型）：列表，元祖，字典

3 取值方式

直接取值：数字

序列类型：字符串，元祖，列表

映射类型：字典

一 整数类型（int）

由数字组成的，主要记下面的一个属性

bit_lenght  ： 显示该数字所对应的二进制数的位数。

二 字符串类型（str）

字符串格式："内容"       ###引号中间所包含的内容这个整体就叫做字符串

相对应的属性

　upper：将字符串内容大写
　a="alEx"
　print(a.upper())

　lower ：将字符串内容小写
　a="alEx"
　print(a.lower())

　capitalize：首字母大写
　a="alEx"
　print(a.capitalize())

　strip：去掉两边的空格
　a=" alEx "
　print(a.strip())

　lstrip ：去除开始位置的空格
　a=" alEx "
　print(a.lstrip())

　rstrip：去除最后位置的空格
　a=" alEx "
　print(a.rstrip())

　replace：替换摸个内容（里面有两个值，一个是要替换的值，一个是新值）
　a=" alEx "
　print(a.replace('x','b'))

　split ： 分割
　a=" alEx "
　print(a.split("l"))

　startswith ：以什么开头
　name=" aleX"
　print(name.startswith("al"))

　endswith：以什么结尾
　name=" aleX"
　print(name.endswith("X"))

　len ：计算长度
　a="alExffsdggdsggsg"
　print(len(a))
　[ ]   ： 索引取值
　a="alExffsdggdsggsg"
　# print(a[5])
　# print(a[len(a)-1])
　# print(a[2:6])
　# print(a[0:-1:3])

　for循环取值
　a="alExffsdggdsggsg"
　for i in a:
    print(i)

三 布尔类型（bool）

　　布尔类型只有两个值，True和False

　　布尔类型没用任何属性

四 数据类型转换

　　布尔值，整数和字符串直接都可以进行数据转换

　　注意：只有数字类型中0 和空的字符串才会返回结果False，其他都是True。

五 列表（list）

　　[ ]一种括号包含的内容，这一个整体就叫做列表。列表的元素之间是以都好（，）分开的，而列表里面的元素的元素可以为任意的数据类型

　相对应的属性：

　append：在列表的尾部添加元素
　a=[11,22,3,56]
　a.append(6)
　print(a)

　insert ：插入
　a=[11,22,3,56] 　
　a.insert(2,98) 　
　print(a)　

　reverse ：反转（将列表的顺序反过来排序）
　a=[11,22,3,56]
　a.reverse()
　print(a)
 　
　len ： 长度
　a=[11,22,3,56]
　print(len(a))

　[ ] ：索引取值
　a=[11,22,3,56]
　print(a[0:4:2])

　替换：
　a=[11,22,3,56]
　a[2:4]=["fang",18]
  print(a)

　del：删除
　a=[11,22,3,56]
　del a[2:4]
　print(a)

　for循环取值
　a=[11,22,3,56]
　for i in a:
　    print(i)

　注意：
　a=[11,22,31,4,[1,2,3,56],'fafng',88]
　a[-2]=a[-2].replace("fng",'ng')
　print(a)

六 元组（tuple）

　　（）以小括号包含的内容，这一个整体叫做元祖，元祖的元素之间也是以都好（，）分开的，里面的元素可以是任意数据类型

　　元祖的子元素是不可以操作的，但是元祖的子子元素有可能可以去操作。
　相对应的功能只有共有的，没有私有的额共能

　　len ：数据长度
　　a=(2,3,1,6)
　　print(len(a))

　　[ ] ：索引取值
　　a=(2,3,1,6)
　　print(a[0:4:2])

　　for循环取值
　　a=(2,3,1,6)
　　for i in a:
    　print(i)

七 字典（dict）

　{ } 以大括号包含，并且是一个key对应一个value组成的键值对称为字典，字典的元素之间也是以都好（，）分开的。里面的value值是可以任意类型的。

　key属性是不可以更改的，不可操作。字典是无序的。相对应的属性：

　get ：取值（以key取值，没有对应的key也不会报错，则会返回一个None，如果给那个key赋一个value值，就会返回这个value值）
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(a.get('name'))

　keys：取所有的key（结合for循环使用）
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(a.keys())

　values ：取所有的value（结合for循环使用）
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(a.values())

　items ：取所有的元素（结合for循环使用）
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(a.items())

　　　len：计算长度
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(len(a))

 　[ ] ：索引取值（以key取值）
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　print(a['name'])

　for循环取值
　　a={
    　　'name':"fang",
    　　"age":18
　　}

　　for i in a.keys():
    　　print(i)

　　a={
    　　'name':"fang",
   　　 "age":18
　　}
　　for a in a.values():
   　　 print(a)

　　a={
   　　 'name':"fang",
   　　 "age":18
　　}

　　for x,y in a.items():
   　　 print(x,y)