Python全栈开发之2、数据类型-数值、字符串、列表、字典、元组和文件处理

一、Python 运算符

1、算术运算：

2、比较运算：

3、赋值运算：

4、逻辑运算：

5、成员运算：

二、基本数据类型

1、数字整型

int（整型）

　　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

 

 #返回表示该数字的时占用的最少位数
         >>> (951).bit_length()
         10
 
 #返回绝对值
         >>> (95).__abs__()
         95
         >>> (-95).__abs__()
         95
 
 #用来区分数字和字符串的
         >>> (95).__add__(1)
         96
         >>> (95).__add__("")
         NotImplemented
 
 #判断一个整数对象是否为0，如果为0,则返回False，如果不为0，则返回True
         >>> (95).__bool__()
         True
         >>> (0).__bool__()
         False
 
 #判断两个值是否相等
         >>> (95).__eq__(95)
         True
         >>> (95).__eq__(9)
         False
 
 #判断是否不等于
         >>> (95).__ne__(9)
          True
         >>> (95).__ne__(95)
         False
 
 #判断是否大于等于
         >>> (95).__ge__(9)
         True
         >>> (95).__ge__(99)
         False
 
 #判断是否大于
         >>> (95).__gt__(9)
         True
         >>> (95).__gt__(99)
         False
 
 #判断是否小于等于
         >>> (95).__le__(99)
         True
         >>> (95).__le__(9)
         False
 
 #判断是否小于
         >>> (95).__lt__(9)
          False
         >>> (95).__lt__(99)
         True
 
 #加法运算
         >>> (95).__add__(5)
         100
 
 #减法运算
         >>> (95).__sub__(5)
         90
 
 #乘法运算
         >>> (95).__mul__(10)
         950
 
 #除法运算
         >>> (95).__truediv__(5)
         19.0
 
 #取模运算
         >>> (95).__mod__(9)
         5
 
 #幂运算
         >>> (2).__pow__(10)
         1024
 
 #整除，保留结果的整数部分
         >>> (95).__floordiv__(9)
         >>>
 
 #转换为整型
         >>> (9.5).__int__()
         9
 
 #返回一个对象的整数部分
         >>> (9.5).__trunc__()
         9
 
 #将正数变为负数，将负数变为正数
         >>> (95).__neg__()
         -95
         >>> (-95).__neg__()
         95
 
 #将一个正数转为字符串
         >>> a = 95
         >>> a = a.__str__()
         >>> print(type(a))
          <class 'str'>
 
 #将一个整数转换成浮点型
         >>> (95).__float__()
         95.0
 
 #转换对象的类型
         >>> (95).__format__('f')
         '95.000000'
         >>> (95).__format__('b')
         ''
 
 #在内存中占多少个字节
         >>> a = 95
         >>> a.__sizeof__()
         28

int方法

 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__
         """
         int.bit_length() -> int
 
         Number of bits necessary to represent self in binary.
         """
         """
         表示该数字返回时占用的最少位数
 
         >>> (951).bit_length()
         10
         """
         return 0
 
     def conjugate(self, *args, **kwargs): # real signature unknown
         """ Returns self, the complex conjugate of any int."""
 
         """
         返回该复数的共轭复数
 
         #返回复数的共轭复数
         >>> (95 + 11j).conjugate()
         (95-11j)
         #返回复数的实数部分
         >>> (95 + 11j).real
         95.0
         #返回复数的虚数部分
         >>> (95 + 11j).imag
         11.0
         """
         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.
         """
         """
         这个方法是在Python3.2的时候加入的,python官方给出了下面几个例子：
         >>> int.from_bytes(b'\x00\x10', byteorder='big')
         >>> int.from_bytes(b'\x00\x10', byteorder='little')
         >>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=True)
         -1024
         >>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=False)
         >>> int.from_bytes([255, 0, 0], byteorder='big')
         """
         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.
         """
         """
         python官方给出了下面几个例子：
         >>> (1024).to_bytes(2, byteorder='big')
         b'\x04\x00'
         >>> (1024).to_bytes(10, byteorder='big')
         b'\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00'
         >>> (-1024).to_bytes(10, byteorder='big', signed=True)
         b'\xff\xff\xff\xff\xff\xff\xff\xff\xfc\x00'
         >>> x = 1000
         >>> x.to_bytes((x.bit_length() // 8) + 1, byteorder='little')
         b'\xe8\x03'
         """
         pass
 
     def __abs__(self, *args, **kwargs): # real signature unknown
         """ abs(self)"""
 
         """
         返回一个绝对值
 
         >>> (95).__abs__()
         -95
         >>> (-95).__abs__()
         95
         """
         pass
 
     def __add__(self, *args, **kwargs): # real signature unknown
         """ Return self+value."""
 
         """
         加法，也可区分数字和字符串
 
         >>> (95).__add__(1)
         96
         >>> (95).__add__("1")
         NotImplemented
         >>>
         """
         pass
 
     def __and__(self, *args, **kwargs): # real signature unknown
         """ Return self&value."""
         pass
 
     def __bool__(self, *args, **kwargs): # real signature unknown
         """ self != 0 """
 
         """
         判断一个整数对象是否为0，如果为0,则返回False，如果不为0，则返回True
 
         >>> (95).__bool__()
         True
         >>> (0).__bool__()
         False
         """
         pass
 
     def __ceil__(self, *args, **kwargs): # real signature unknown
         """ Ceiling of an Integral returns itself. """
         pass
 
     def __divmod__(self, *args, **kwargs): # real signature unknown
         """ Return divmod(self, value). """
         """
         返回一个元组，第一个元素为商，第二个元素为余数
 
         >>> (9).__divmod__(5)
         (1, 4)
         """
         pass
 
     def __eq__(self, *args, **kwargs): # real signature unknown
         """ Return self==value. """
         """
         判断两个值是否相等
 
         >>> (95).__eq__(95)
         True
         >>> (95).__eq__(9)
         False
         """
         pass
 
     def __float__(self, *args, **kwargs): # real signature unknown
         """ float(self) """
         """
         将一个整数转换成浮点型
 
         >>> (95).__float__()
         95.0
         """
         pass
 
     def __floordiv__(self, *args, **kwargs): # real signature unknown
         """ Return self//value. """
         """
         整除，保留结果的整数部分
 
         >>> (95).__floordiv__(9)
         10
         """
         pass
 
     def __floor__(self, *args, **kwargs): # real signature unknown
         """ Flooring an Integral returns itself. """
         """
         返回本身
 
         >>> (95).__floor__()
         95
         """
         pass
 
     def __format__(self, *args, **kwargs): # real signature unknown
         """
         转换对象的类型
 
         >>> (95).__format__('f')
         '95.000000'
         >>> (95).__format__('b')
         '1011111'
         """
         pass
 
     def __getattribute__(self, *args, **kwargs): # real signature unknown
         """ Return getattr(self, name). """
         """
         判断这个类中是否包含这个属性，如果包含则打印出值，如果不包含，就报错了
 
         >>> (95).__getattribute__('__abs__')
         <method-wrapper '__abs__' of int object at 0x9f93c0>
         >>> (95).__getattribute__('__aaa__')
         Traceback (most recent call last):
         File "<stdin>", line 1, in <module>
         AttributeError: 'int' object has no attribute '__aaa__'
         """
         pass
 
     def __getnewargs__(self, *args, **kwargs): # real signature unknown
         pass
 
     def __ge__(self, *args, **kwargs): # real signature unknown
         """ Return self>=value. """
         """
         判断是否大于等于
 
         >>> (95).__ge__(9)
         True
         >>> (95).__ge__(99)
         False
         """
         pass
 
     def __gt__(self, *args, **kwargs): # real signature unknown
         """ Return self>value. """
         """
         判断是否大于
 
         >>> (95).__gt__(9)
         True
         >>> (95).__gt__(99)
         False
         """
         pass
 
     def __hash__(self, *args, **kwargs): # real signature unknown
         """ Return hash(self). """
         """
         计算哈希值，整数返回本身
 
         >>> (95).__hash__()
         95
         >>> (95.95).__hash__()
         2190550858753015903
         """
         pass
 
     def __index__(self, *args, **kwargs): # real signature unknown
         """ 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__
         """
          这个是一个类的初始化方法，当int类被实例化的时候，这个方法默认就会被执行
         """
         """
         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) """
         """
         转换为整型
 
         >>> (9.5).__int__()
         9
         """
         pass
 
     def __invert__(self, *args, **kwargs): # real signature unknown
         """ ~self """
 
         pass
 
     def __le__(self, *args, **kwargs): # real signature unknown
         """ Return self<=value. """
         """
         判断是否小于等于
 
         >>> (95).__le__(99)
         True
         >>> (95).__le__(9)
         False
         """
         pass
 
     def __lshift__(self, *args, **kwargs): # real signature unknown
         """ Return self<<value. """
         """
         用于二进制位移，这个是向左移动
 
         >>> bin(95)
         '0b1011111'
         >>> a = (95).__lshift__(2)
         >>> bin(a)
         '0b101111100'
          >>>
         """
         pass
 
     def __lt__(self, *args, **kwargs): # real signature unknown
         """ Return self<value. """
         """
         判断是否小于
 
         >>> (95).__lt__(9)
         False
         >>> (95).__lt__(99)
         True
         """
         pass
 
     def __mod__(self, *args, **kwargs): # real signature unknown
         """ Return self%value. """
         """
         取模 %
 
         >>> (95).__mod__(9)
         """
         pass
 
     def __mul__(self, *args, **kwargs): # real signature unknown
         """ Return self*value. """
         """
         乘法 *
 
         >>> (95).__mul__(10)
         """
         pass
 
     def __neg__(self, *args, **kwargs): # real signature unknown
         """ -self """
         """
         将正数变为负数，将负数变为正数
 
         >>> (95).__neg__()
         -95
         >>> (-95).__neg__()
         95
         """
         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. """
         """
         不等于
 
         >>> (95).__ne__(9)
         True
         >>> (95).__ne__(95)
         False
         """
         pass
 
     def __or__(self, *args, **kwargs): # real signature unknown
         """ Return self|value. """
         """
         二进制或的关系，只要有一个为真，就为真
 
         >>> a = 4
         >>> b = 0
         >>> a.__or__(b)     # a --> 00000100        b --> 00000000
         >>> b = 1           # b --> 00000001
         >>> a.__or__(b)
         """
         pass
 
     def __pos__(self, *args, **kwargs): # real signature unknown
         """ +self """
         pass
 
     def __pow__(self, *args, **kwargs): # real signature unknown
         """ Return pow(self, value, mod). """
         """
         幂
 
         >>> (2).__pow__(10)
         1024
         """
         pass
 
     def __radd__(self, *args, **kwargs): # real signatre unknown
         """ Return value+self. """
         """
         加法，将value放在前面
 
         >>> a.__radd__(b)       # 相当于 b+a
         """
         pass
 
     def __rand__(self, *args, **kwargs): # real signature unknown
         """ Return value&self. """
         """
         二进制与的关系，两个都为真，才为真，有一个为假，就为假
         """
         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 """
         """
         在内存中占多少个字节
 
         >>> a = 95
         >>> a.__sizeof__()
         28
         """
         pass
 
     def __str__(self, *args, **kwargs): # real signature unknown
         """ Return str(self). """
         """
         将一个正数转为字符串
 
         >>> a = 95
         >>> a = a.__str__()
         >>> print(type(a))
         <class 'str'>
         """
         pass
 
     def __sub__(self, *args, **kwargs): # real signature unknown
         """ Return self-value. """
         """
         减法运算
 
         >>> (95).__sub__(5)
         90
         """
         pass
 
     def __truediv__(self, *args, **kwargs): # real signature unknown
         """ Return self/value. """
         """
         除法运算
 
         >>> (95).__truediv__(5)
         19.0
         """
         pass
 
     def __trunc__(self, *args, **kwargs): # real signature unknown
         """ Truncating an Integral returns itself. """
         """
         返回一个对象的整数部分
 
         >>> (95.95).__trunc__()
         95
         """
         pass
     def __xor__(self, *args, **kwargs): # real signature unknown
         """ Return self^value. """
         """
         将对象与值进行二进制的或运算，一个为真，就为真
 
         >>> a = 4
         >>> b = 1
         >>> a.__xor__(b)
         >>> c = 0
         >>> a.__xor__(c)
         """
 
         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 """
     """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 """
     """the real part of a complex number"""

int

2、字符串

"hello  world"

str（字符串类型）

万恶的字符串拼接：

字符串一旦创建不可修改，一旦修改或者拼接，都会重新生成字符串

python中的字符串在C语言中体现为是一个字符数组，每次创建字符串时候需要在内存中开辟一块连续的空，并且一旦需要修改字符串的话，就需要再次开辟空间，万恶的+号每出现一次就会在内存中重新开辟一块空间。

 #切片
 
 #索引，从0号索引开始,获取字符串中的某一个字符
 string="allen中文"
 print(string[0])
 
 #索引范围
 print(string[0:2])
 
 #获取最后一个索引位置
 print(string[-1])
 
 print(string[0:-1])
 #输出: alle
 
 #len()获取字符串长度
 len(string)
 print("_".join(string))
 
 #列子
 index=0
 while index<len(string):
     print(string[index])
     index+=1
 
 #字符串替换
 new_string=string.replace('en','EN')
 print(new_string)
 #输出: allEN中文

切片

 #查看类型
 age=18
 my_name="obama"
 
 print(type(age))
 print(type(my_name))
 #输出 :
 #    <class 'int'>
 #    <class 'str'>
 
 #将字符串转换为整型
 number=""
 num= int(number)
 print(type(num),num)
 
 #输出: <class 'int'> 123
 
 #首字母转换为大写,其他字母都是小写
 name ='my name is AllEn'
 print(name.capitalize())
 # 输出：My name is allen
 
 #所有字符转换为小写，比lower()更牛逼
 print(name.casefold())
 # 输出：my name is allen
 
 #统计m出现次数
 print(name.count("m"))
 # 输出：2
 
 #把name变量放在50个字符中间，设置宽度并把内容居中
 print(name.center(50,'-'))
 # 输出：-----------------my name is AllEn-----------------
 
 #判断一个字符串是否以en结尾
 print(name.endswith('En'))
 # 输出：True
 
 #判断一个字符串是否以my开始
 print(name.startswith('my'))
 # 输出：True
 
 #查找子序列name，找到返回其索引，找不到返回-1
 print(name.find('name'))
 
 # 输出：3
 
 #字符串切片
 print(name[name.find('name'):])
 # 输出：name is AllEn
 
 #format格式化用法1: 将字符串占位符替换为指定的值
 name_info='my name is {_name} and I am {_age} old'
 #
 #
 print(name_info.format(_name='allen',_age=18))
 # 输出：my name is allen and I am 18 old
 
 #format格式化用法2:根据顺序替换
 name_info1='my name is {0} and I am {1} old'
 
 print(name_info1.format('allen',18))
 # 输出：my name is allen and I am 18 old
 
 #format_map 字典用法
 print(name_info.format_map({'_name':'allen','_age':20}))
 # 输出：my name is allen and I am 20 old
 
 #查找索引，如果找不到会报错
 print(name.index('name'))
 # 输出：3
 
 #判断是否包含数字和字母
 print('9aA'.isalnum())
 # 输出：True
 
 #判断是否包含纯英文字符
 print('abA'.isalpha())
 
 # 输出：True
 
 # 判断是否是整数
 print(''.isdigit())
 
 # 输出：True
 
 #判断是否是数字,支持unicode
 test="二"
 print(test.isnumeric(),test)
 # 输出：True
 
 #判断是不是合法的变量名
 print('1A'.isidentifier())
 
 # 输出：False
 
 #判断是否是小写
 print('abc'.islower())
 # 输出：True
 
 #判断是否是大写
 print('33a'.isupper())
 # 输出:False
 
 # 大小写互换
 print('AllEN'.swapcase())
 # 输出：aLLen
 
 #字符串替换，只替换一次
 print('AlLeN'.replace('l','L',1))
 # 输出：ALLeN
 
 #join连接两个字符串
 li = ["nick","serven"]
 a = "".join(li)
 b = "_".join(li)
 print(a)
 print(b)
 
 #输出:nickserven
 #    nick_serven
 
 #大写变小写
 print('ALLen'.lower())
 # 输出：allen
 
 # 小写变大写
 print('allen'.upper())
 # 输出：ALLEN
 
 #去掉左右的空格(包括换行符和制表符)
 print('   all\ne\tn '.strip())
 # 输出:allen
 
 #去掉左边空行和回车
 print('   allen  '.lstrip())
 # 输出：allen
 
 #去掉右边空行和回车
 print('  allen  '.rstrip())
 # 输出：  allen
 
 #找到最右边目标的索引
 print('allenlaen'.rfind('a'))
 # 输出：6
 
 #判断是否全部是空格
 test=" "
 print(test.isspace())
 # 输出：True
 
 #判断是否是标题(首字母全部是大写)
 title="Return the highest index in S where substring sub"
 print(title.istitle(),title)
 # 输出:False
 # 转换为首字母全部为大写(转换为标题)
 print(title.title())
 # 输出:Return The Highest Index In S Where Substring Sub
 
 #字符串切割 以t切分  t没有了
 print('allen test'.split('t'))
 # 输出：['allen ', 'es', '']
 
 #字符串切割 以t切分，只分割一次
 print('allen test'.split('t',1))
 # 输出：['allen ', 'est']
 
 #只根据换行符分割
 print("asdsad\nasdsad\nasda".splitlines())
 
 #输出:['asdsad', 'asdsad', 'asda']
 
 #表示长度50 不够右边*号填充
 print(name.ljust(50,'*'))
 # 输出：my name is AllEn**********************************
 
 # 表示长度50 不够左边-号填充
 print(name.rjust(50,'-'))
 # 输出：----------------------------------my name is AllEn

str方法

 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__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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
         """
         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__
         """
         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
 
         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.
 
         Raises ValueError when the substring is not found.
         """
         return 0
 
     def isalnum(self): # real signature unknown; restored from __doc__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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
 
         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.
 
         Raises 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__
         """
         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__
         """
         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__
         """
         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__
         """
         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__
         """
         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 ""

str

 #range创建连续的数字
 
 for item in range(0,100):
     print(item)
 #设置步长
 for item in range(0,100,2):
     print(item)

range

# -*- coding:utf-8 -*-
# Author:sunhao
 
name=input('username:')
age=int(input('age:'))
job=input('job:')
salary=int(input('salary:'))
 
info='''
--------info of %s----------
Name:%s
Age:%d
Job:%s
Salary:%d
'''%(name,name,age,job,salary)    #第一种表示方法
 
info2='''
--------info of {_name}----------
Name:{_name}
Age:{_age}
Job:{_job}
Salary:{_salary}
'''.format(_name=name,
           _age=age,
           _job=job,
           _salary=salary)     #第二种表示方法  .format()
 
info3='''
--------info of {0}----------
Name:{0}
Age:{1}
Job:{2}
Salary:{3}
'''.format(name,
           age,
           job,
           salary)              #第三种表示方法
 
print(info1)
print(info2)
print(info3)
 
#三种显示结果是一样的

format()使用方法

3、列表

通过list类创建的对象

names=['Lily','Tom','Lucy','Hanmeimei']

通过下标访问列表中的元素，下标从0开始：

In[3]: names = ['Lily', 'Tom', 'Lucy', 'Hanmeimei']
 
In[4]: names[0]
Out[4]: 'Lily'
 
In[5]: names[1]
Out[5]: 'Tom'
 
In[6]: names[-1]
Out[6]: 'Hanmeimei'
 
In[7]: names[-2]
Out[7]: 'Lucy'

>>> names = ["Alex","Tenglan","Eric","Rain","Tom","Amy"]
>>> names[1:4]  #取下标1至下标4之间的数字，包括1，不包括4
['Tenglan', 'Eric', 'Rain']
>>> names[1:-1] #取下标1至-1的值，不包括-1
['Tenglan', 'Eric', 'Rain', 'Tom']
>>> names[0:3]
['Alex', 'Tenglan', 'Eric']
>>> names[:3] #如果是从头开始取，0可以忽略，跟上句效果一样
['Alex', 'Tenglan', 'Eric']
>>> names[3:] #如果想取最后一个，必须不能写-1，只能这么写
['Rain', 'Tom', 'Amy']
>>> names[3:-1] #这样-1就不会被包含了
['Rain', 'Tom']
>>> names[0::2] #后面的2是代表，每隔一个元素，就取一个
['Alex', 'Eric', 'Tom']
>>> names[::2] #和上句效果一样
['Alex', 'Eric', 'Tom']

切片

list.append()   #列表追加元素 只是追加在列表的尾部
 
list1=['apple','orange','peach','watermelon']
 
list1.append('banana')    #往列表中添加一个元素
 
print (list1)
['apple', 'orange', 'peach', 'watermelon', 'banana']

追加元素

不能批量插入
 
list.insert(index, object)   #往列表中插入一个元素
 
例如：
 
list1=['apple','orange','peach','watermelon']
 
list1.insert(1,'Lemon')  #在列表第一个位置插入Lemon这个元素
 
print (list1)
 
['apple', 'Lemon', 'orange', 'peach', 'watermelon', 'banana']

insert插入元素

list1=['apple','orange','peach','watermelon']
 
list1[2]='fruit'   #把peach修改为fruit
 
print(list1)
 
输出：
['apple', 'Lemon', 'fruit', 'peach', 'watermelon', 'banana']   #peach被修改为 fruit

修改

删除有两种方法：
 
第一种 list.remove()
 
list1=['apple', 'Lemon', 'orange', 'peach', 'watermelon', 'banana']
 
list1.remove('apple')   #remove方法
 
输出：
print (list1)
 
['Lemon', 'fruit', 'peach', 'watermelon', 'banana']　　
 
第二种 按下标方法删除
 
del list1[1]  #删除列表中第1个元素

remove删除

list.pop()  # 默认是从列表中一次弹出最后一个元素  
 
list.pop(1) # 如果输入下标  等于 del list1[1] 方法

pop弹出元素

list.index()  #查找元素的位置
 
list1=['Lemon', 'fruit', 'peach', 'watermelon', 'banana']
 
list1.index('peach')  #查找peach的位置
 
输出：2               #索引的位置为2
 
print(list1[list1.index('peach')])
 
输出：peach

index索引查找元素的位置

如果一个列表中有重复的元素，需要统计重复元素的个数
 
list.count()
例如：
 
list1=['banana','peach','watermelon','banana','peach','apple','banana']
 
list1.count('banana') #统计列表中banana 的数量
 
输出：
3

count统计元素重复个数

list.clear()

clear清空列表

list.reverse()
 
list1=['banana', 'peach', 'watermelon', 'banana','peach','apple','tomato','banana']
 
list1.reverse()
 
print (list1)
 
['banana', 'tomato', 'apple', 'peach', 'banana', 'watermelon', 'peach', 'banana']   #元素反转 位置改变

reverse元素反转

list.sort()
 
list1=['banana', 'peach', 'watermelon', 'banana','peach','apple','tomato','banana']
 
list1.sort()
 
print(list1)
 
['apple', 'banana', 'banana', 'banana', 'peach', 'peach', 'tomato', 'watermelon']  #按照字母排序

sort元素排序

list.extend()
 
#两个列表
list1=['banana', 'peach', 'watermelon', 'banana','peach','apple','tomato','banana']
 
list2=['lily','Lucy','Tom']
 
list1.extend(list2)  #把list1和list2合并
 
print(list1)
 
输出：
['apple', 'banana', 'banana', 'banana', 'peach', 'peach', 'tomato', 'watermelon', 'lily', 'Lucy', 'Tom']   # 两个列表合并

extend多个列表合并元素

names=['lucy','Lily','Jim','age']
 
new_names="".join(names)
print(new_names)

列表转换成字符串

4、元组(不可变列表)

元组一级元素不可被修改和删除。但是，元组中嵌套列表可以被修改

tu3=(111,222,[(333,444)],555,(666,777),)
 
tu3[2][0]=888
print(tu3)
#输出:(111, 222, [888], 555, (666, 777))

创建元组：

tuple=('tom','lily',1,2,)   一般写元组时，建议在最后加一个逗号

 class tuple(object):
     """
     tuple() -> empty tuple
     tuple(iterable) -> tuple initialized from iterable's items
 
     If the argument is a tuple, the return value is the same object.
     """
     def count(self, value): # real signature unknown; restored from __doc__
         """ T.count(value) -> integer -- return number of occurrences of value """
         return 0
 
     def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
         """
         T.index(value, [start, [stop]]) -> integer -- return first index of value.
         Raises ValueError if the value is not present.
         """
         return 0
 
     def __add__(self, *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 __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, seq=()): # known special case of tuple.__init__
         """
         tuple() -> empty tuple
         tuple(iterable) -> tuple initialized from iterable's items
 
         If the argument is a tuple, the return value is the same object.
         # (copied from class doc)
         """
         pass
 
     def __iter__(self, *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 __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 __rmul__(self, *args, **kwargs): # real signature unknown
         """ Return self*value. """
         pass

tuple方法

str1="Mypython"
 
tu1=tuple(str1)
 
print(tu1)
 
#输出:('M', 'y', 'p', 'y', 't', 'h', 'o', 'n')

字符串转换成元组

names=['lucy','Lily','Jim','age']
 
tu2=tuple(names)
print(tu2)
#输出:('lucy', 'Lily', 'Jim', 'age')

列表转换成元组

name2=('lucy', 'Lily', 'Jim', 'age')
 
list1=list(name2)
 
print(list1)
#输出:['lucy', 'Lily', 'Jim', 'age']

元组转换成列表

5、字典

字典一种key - value 的数据类型

字典的特性：

• dict是无序的
• key必须是唯一的,所以自动去重

语法：

user_info={
     '':'Tom',
     '':'Jim',
     '':'Lucy',
     '':'Lily'
 }

a = user_info.keys()
print(a)

获取所有的key列表keys()

#根据key获取值
a = user_info.get("age")
print(a)
 
#如果没有值，返回None，不报错
 
a = user_info.get("Age",19")
print(a)
 
#如果没有值，就返回19

根据key获取值get()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
 
print(user_info.values())
 
#返回 dict_values(['nick', 18, 'pythoner'])

获取所有的value列表values()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
 
print(user_info.items())
 
#输出：dict_items([('name', 'nick'), ('age', 18), ('job', 'pythoner')])

items()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
#第一种删除方法
print(user_info.pop('name'))
 
#输出{'age': 18, 'job': 'pythoner'}
 
#第二种随机删除字典里的key和value
 
print(user_info.popitem())

删除pop()和随机删除popitem()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
user_info2 = {
    "wage":800000000,
    "drem":"The knife girl",
    "name":"jack"
}
#有交叉的就覆盖了 没有交叉就创建
user_info.update(user_info2)
 
print(user_info)
#输出：{'name': 'jack', 'age': 18, 'job': 'pythoner', 'wage': 800000000, 'drem': 'The knife girl'}

两个字典更新update()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
#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
 
print(user_info.setdefault('slary',5000))
print(user_info)

setdefault()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
 
print(user_info.clear())
print(user_info)
 
#输出：{}

清空字典clear()

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
 
del user_info['name']
 
print(user_info)
 
#输出：{'age': 18, 'job': 'pythoner'}

del删除元素

#根据序列，创建字典并指定统一的值
 
info=dict.fromkeys(['slary','number'],5000)
 
print(info)
 
#输出：{'slary': 5000, 'number': 5000}

dict.fromkeys()

province={
 
        '广东省':{'深圳市':['南山区','龙岗区','福田区'],
                       '广州市':['荔湾区','海珠区','天河区'],
                        '惠州市':['惠阳区','惠城区','惠东县']},
 
        '浙江省':{'杭州市':['西湖区','上城区','下城区'],
                     '宁波市':['江北区','镇海区'],
                        '嘉兴市':['南湖区','秀洲区']}
}
 
print(province['广东省'])
 
{'深圳市': ['南山区', '龙岗区', '福田区'], '广州市': ['荔湾区', '海珠区', '天河区'], '惠州市': ['惠阳区', '惠城区', '惠东县']}

多级字典嵌套及操作

province={
 
        '广东省':{'深圳市':['南山区','龙岗区','福田区'],
                       '广州市':['荔湾区','海珠区','天河区'],
                        '惠州市':['惠阳区','惠城区','惠东县']},
 
        '浙江省':{'杭州市':['西湖区','上城区','下城区'],
                     '宁波市':['江北区','镇海区'],
                        '嘉兴市':['南湖区','秀洲区']}
}
 
for k,v in province.items():
    print(k,v)

字典for循环

user_info = {
    "name":"nick",
    "age":18,
    "job":"pythoner"
}
user_info2 = {
    "wage":800000000,
    "drem":"The knife girl",
    "name":"jack"
}
#有交叉的就覆盖了 没有交叉就创建
user_info.update(user_info2)
或者
user_info.update( "wage"=800000000, "drem"="The knife girl")
 
print(user_info)
#输出：{'name': 'jack', 'age': 18, 'job': 'pythoner', 'wage': 800000000, 'drem': 'The knife girl'}

update()补充

6、set()集合

集合是一个无序的，不重复的数据组合，它的主要作用如下：

• 去重，把一个列表变成集合，就自动去重了
• 关系测试，测试两组数据之前的交集、差集、并集等关系
• 集合中元素必须是不可变类型，不能包含列表、字典
• 集合只可以追加、删除，但是不可修改

#列表
list1=[1,4,5,7,3,6,7,9]   
 
# 创建集合  集合也是无序的
set1=set(list1)            
 
print(set1,type(set1))
 
set2=set([2,6,0,66,22,8,4])
 
print(set1,set2)
 
#输出：
{1, 3, 4, 5, 6, 7, 9} <class 'set'>
{1, 3, 4, 5, 6, 7, 9} {0, 2, 66, 4, 6, 8, 22}

创建集合

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
print(set1.intersection(set2))
 
#输出:{4, 6}

交集intersection()

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#求并集两个集合去重合并
 
print(set1.union(set2))
#输出：{0, 1, 2, 3, 4, 5, 6, 7, 66, 9, 8, 22}

并集union()

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#set1中有 set2中没有的元素
print(set1.difference(set2))
 
#输出:{1, 3, 5, 7, 9}
 
#set2中有 set1中没有的元素
print(set2.difference(set1))
 
#输出:{0, 2, 66, 8, 22}

差集difference()

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#求子集
 
#判断set1是否是set2的子集
print(set1.issubset(set2))
 
#判断set2是否是set1的子集
print(set2.issubset(set1))

子集issubset()

#求父集
 
list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
# 判断set1是否是set2的父集
print(set1.issuperset(set2))
 
# 判断set2是否是set1的父集
print(set2.issuperset(set1))

父集issuperset()

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#对称差集
 
print(set1.symmetric_difference(set2))
 
#输出：
{0, 1, 2, 66, 3, 5, 8, 7, 9, 22}

对称差集symmetric_difference()

list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#如果两个集合没有交集返回True 否则返回False
 
print(set1.isdisjoint(set2))
 
#输出：False

两个集合没有交集返回True

print(set1 & set2) #交集
 
print(set1 | set2) #并集
 
print(set1 - set2)  #差集
 
print(set1 ^ set2)  #对称差集
 
list1=[1,4,5,7,3,6,7,9]
 
set1=set(list1)
 
set2=set([2,6,0,66,22,8,4])
 
#集合中是没有插入的，只能添加
 
set1.add(2)  # 添加一项
 
set3 = set([100, 200, 300])
 
set1.update(set3)  # 只能把一个集合更新到另一个集合中
 
set1.remove(100)  # 删除集合中一个元素
set1.discard(100)  # 删除一个元素 如果这个元素没有 不会报错  而remove会报错

集合其他基本操作

# -*-coding:utf-8-*-
# Author:sunhao
 
product_list=[('Iphone',5800),
              ('Mac Pro',12000),
              ('Bike',800),
              ('Watch',10600),
              ('coffee',31)
              ]
shopping_list=[]
 
salary=input('请输入你的工资：')
if salary.isdigit():
    salary=int(salary)
    while True:
        for index,item in enumerate(product_list):
            print(index,item)
        user_choice=input("请选择要买的商品：")
        if user_choice.isdigit():
            user_choice=int(user_choice)
            if user_choice<len(product_list) and user_choice >=0:
                p_item=product_list[user_choice]
                print(p_item)
                if p_item[1] <= salary:
                    shopping_list.append(p_item)
                    salary -= p_item[1]
                    print('%s已添加至购物车 ,余额为%d'%(p_item[0],salary))
 
                else:
                    print("\033[41;1m你的余额只剩%s\033[0m"%salary)
 
            else:
                print("商品不存在")
 
        elif user_choice=='q':
            print("-------shoppinglist------")
            for p in shopping_list:
                print(p[0])
            print('-------------------------')
            print('Your current balance:%s'%salary)
            exit()
        else:
            print('Invalid choice')

练习-购物车程序

三、文件处理

1、文件操作

对文件操作流程

1. 打开文件，得到文件句柄并赋值给一个变量
2. 通过句柄对文件进行操作
3. 关闭文件

Somehow, it seems the love I knew was always the most destructive kind
不知为何，我经历的爱情总是最具毁灭性的的那种
Yesterday when I was young
昨日当我年少轻狂
The taste of life was sweet
生命的滋味是甜的
As rain upon my tongue
就如舌尖上的雨露
I teased at life as if it were a foolish game
我戏弄生命 视其为愚蠢的游戏
The way the evening breeze
就如夜晚的微风
May tease the candle flame
逗弄蜡烛的火苗
The thousand dreams I dreamed
我曾千万次梦见
The splendid things I planned
那些我计划的绚丽蓝图
I always built to last on weak and shifting sand
但我总是将之建筑在易逝的流沙上
I lived by night and shunned the naked light of day
我夜夜笙歌 逃避白昼赤裸的阳光
And only now I see how the time ran away
事到如今我才看清岁月是如何匆匆流逝
Yesterday when I was young
昨日当我年少轻狂
So many lovely songs were waiting to be sung
有那么多甜美的曲儿等我歌唱
So many wild pleasures lay in store for me
有那么多肆意的快乐等我享受
And so much pain my eyes refused to see
还有那么多痛苦 我的双眼却视而不见
I ran so fast that time and youth at last ran out
我飞快地奔走 最终时光与青春消逝殆尽
I never stopped to think what life was all about
我从未停下脚步去思考生命的意义
And every conversation that I can now recall
如今回想起的所有对话
Concerned itself with me and nothing else at all
除了和我相关的 什么都记不得了
The game of love I played with arrogance and pride
我用自负和傲慢玩着爱情的游戏
And every flame I lit too quickly, quickly died
所有我点燃的火焰都熄灭得太快
The friends I made all somehow seemed to slip away
所有我交的朋友似乎都不知不觉地离开了
And only now I'm left alone to end the play, yeah
只剩我一个人在台上来结束这场闹剧
Oh, yesterday when I was young
噢 昨日当我年少轻狂
So many, many songs were waiting to be sung
有那么那么多甜美的曲儿等我歌唱
So many wild pleasures lay in store for me
有那么多肆意的快乐等我享受
And so much pain my eyes refused to see
还有那么多痛苦 我的双眼却视而不见
There are so many songs in me that won't be sung
我有太多歌曲永远不会被唱起
I feel the bitter taste of tears upon my tongue
我尝到了舌尖泪水的苦涩滋味
The time has come for me to pay for yesterday
终于到了付出代价的时间 为了昨日
When I was young
当我年少轻狂

文件示例lyrics

f = open('lyrics','w','encoding=utf-8')  #打开文件  f为文件句柄
 
data = f.read()    #读文件
 
print(data)
 
f.close()  #关闭文件
 
f.readable()  #判断文件是否可读
 
f.writable()  #判断文件是都可写
 
f.closed()    #判断文件是否关闭  返回True 和 False

打开一个文件包含两部分资源：操作系统级打开的文件+应用程序的变量。在操作完毕一个文件时，必须把与该文件的这两部分资源一个不落地回收，回收方法为：
1、f.close() #回收操作系统级打开的文件
2、del f #回收应用程序级的变量
 
其中del f一定要发生在f.close()之后，否则就会导致操作系统打开的文件还没有关闭，白白占用资源，
而python自动的垃圾回收机制决定了我们无需考虑del f，这就要求我们，在操作完毕文件后，一定要记住f.close()
 
我们推荐傻瓜式操作方式：使用with关键字来帮我们管理上下文
with open('a.txt','w') as f:
    pass
 
with open('a.txt','r') as read_f,open('b.txt','w') as write_f:
    data=read_f.read()
    write_f.write(data)

注意f.close()

f=open(...)是由操作系统打开文件，那么如果我们没有为open指定编码，那么打开文件的默认编码很明显是操作系统说了算了，操作系统会用自己的默认编码去打开文件，在windows下是gbk，在linux下是utf-8。
这就用到了上节课讲的字符编码的知识：若要保证不乱码，文件以什么方式存的，就要以什么方式打开。
 
f=open('a.txt','r',encoding='utf-8')

打开文件注意字符编码

2、打开文件的模式

#1. 打开文件的模式有(默认为文本模式)：
r，只读模式【默认模式，文件必须存在，不存在则抛出异常】
w，只写模式【不可读；不存在则创建；存在则清空内容】
a，只追加写模式【不可读；不存在则创建；存在则只追加内容】
 
#2. 对于非文本文件，我们只能使用b模式，"b"表示以字节的方式操作（而所有文件也都是以字节的形式存储的，使用这种模式无需考虑文本文件的字符编码、图片文件的jgp格式、视频文件的avi格式）
rb
wb
ab
注：以b方式打开时，读取到的内容是字节类型，写入时也需要提供字节类型，不能指定编码
 
#3. 了解部分
"+" 表示可以同时读写某个文件
r+， 读写【可读，可写】
w+，写读【可读，可写】
a+， 写读【可读，可写】

"U"表示在读取时，可以将 \r \n \r\n自动转换成 \n （与 r 或 r+ 模式同使用）

rU

r+U

x， 只写模式【不可读；不存在则创建，存在则报错】
x+ ，写读【可读，可写】
xb

3、操作文件的方法

f.read() #读取所有内容,光标移动到文件末尾
f.readline() #读取一行内容,光标移动到第二行首部
f.readlines() #读取每一行内容,存放于列表中
 
f.write('1111\n222\n') #针对文本模式的写,需要自己写换行符
f.write('1111\n222\n'.encode('utf-8')) #针对b模式的写,需要自己写换行符
f.writelines(['333\n','444\n']) #文件模式
f.writelines([bytes('333\n',encoding='utf-8'),'444\n'.encode('utf-8')]) #b模式

f = open('lyrics','r+',encoding='utf-8')
 
for  index,line in enumerate(f.readlines()):
 
    if index ==9:
        print(-------分隔符------)   #第九行打印分隔符 跳出本次循环
        continue
    print(line)

示例

练习，利用b模式，编写一个cp工具，要求如下：

　　1. 既可以拷贝文本又可以拷贝视频，图片等文件

　　2. 用户一旦参数错误，打印命令的正确使用方法，如usage: cp source_file target_file

　　提示：可以用import sys，然后用sys.argv获取脚本后面跟的参数

import sys
if len(sys.argv) != 3:
    print('usage: cp source_file target_file')
    sys.exit()
 
source_file,target_file=sys.argv[1],sys.argv[2]
with open(source_file,'rb') as read_f,open(target_file,'wb') as write_f:
    for line in read_f:
        write_f.write(line)

练习

4、文件内光标移动

f = open('lyrics','r+',encoding='utf-8')
 
print(f.tell())
 
f.read(16)
 
print(f.tell())
 
输出：
0
16

tell()查看文件句柄指针的位置

f = open('lyrics','r+',encoding='utf-8')
 
print(f.tell())
 
f.read(16)
 
print(f.tell())
 
f.seek(0)      #移动到文件字符行首
 
print(f.tell())
输出：
0
16

seek()移动文件句柄指针位置

f = open('lyrics','r+',encoding='utf-8')
 
print(f.encoding())
 
输出：
utf-8

encoding()打印文件的编码

f = open('lyrics','r+',encoding='utf-8')
 
f.flush()

flush()强制刷新到硬盘

# -*-coding:utf-8-*-
import sys,time
 
for i in range(10):
    sys.stdout.write('#')
 
    sys.stdout.flush()     如果不加flush  是等缓存满了之后一次性打印出来    加了之后是打印在一次强制刷新一次
    time.sleep(1)

flush()示例-打印进度条

 truncate是截断文件，所以文件的打开方式必须可写，但是不能用w或w+等方式打开，因为那样直接清空文件了，所以truncate要在r+或a或a+等模式下测试效果

truncate()截断文件

5、文件的修改

文件的数据是存放于硬盘上的，因而只存在覆盖、不存在修改这么一说，我们平时看到的修改文件，都是模拟出来的效果，具体的说有两种实现方式：

方式一：将硬盘存放的该文件的内容全部加载到内存，在内存中是可以修改的，修改完毕后，再由内存覆盖到硬盘（word，vim，nodpad++等编辑器）

import os
 
with open('a.txt') as read_f,open('.a.txt.swap','w') as write_f:
    data=read_f.read() #全部读入内存,如果文件很大,会很卡
    data=data.replace('alex','SB') #在内存中完成修改
 
    write_f.write(data) #一次性写入新文件
 
os.remove('a.txt')
os.rename('.a.txt.swap','a.txt') 

方式二：将硬盘存放的该文件的内容一行一行地读入内存，修改完毕就写入新文件，最后用新文件覆盖源文件

import os
 
with open('a.txt') as read_f,open('.a.txt.swap','w') as write_f:
    for line in read_f:
        line=line.replace('alex','SB')
        write_f.write(line)
 
os.remove('a.txt')
os.rename('.a.txt.swap','a.txt') 

# -*-coding:utf-8-*-
# Author:sunhao
 
f = open('yesterday','r',encoding='utf-8')   #打开要修改的文件
 
f_new = open('yesterday.bak','w',encoding='utf-8')  #再打开一个要写入的新文件
 
for line in f:      #循环旧文件里的每一行
    if "肆意的快乐" in line:        #每一行的type(line)是一个字符串
        line=line.replace("肆意的快乐",'肆意的痛苦')  #字符串替换
 
    f_new.write(line)   #写入新文件
 
f.close()       #关闭旧文件
f_new.close()  #关闭新文件

文件修改-示例

#with语句
为了避免打开文件后忘记关闭，可以通过管理上下文，即：
 
 with  open('file','r','encoding='uth-8'')  as  f:  #f为文件句柄
    for line in f:
        print(line)
 
这样不用关闭文件
 
也可以同时操作多个文件
with open('file1','r','encoding=utf-8') as f1,open('file2','r','encoding=utf-8') as f2:
    pass

with open()管理上下文

import  sys
 
f = open('yesterday','r',encoding='utf-8')
 
f_new = open('yesterday.bak','w',encoding='utf-8')
 
find_str=sys.argv[1]
replace_str=sys.argv[2]
 
for line in f:
    if find_str in line:
        line=line.replace(find_str,replace_str)
 
    f_new.write(line)
 
f.close()
f_new.close()

练习-脚本传参实现sed替换

四、其他

1、字符编码与转码

1.在python2默认编码是ASCII, python3里默认是unicode

2.unicode 分为 utf-32(占4个字节),utf-16(占两个字节)，utf-8(占1-4个字节)， so utf-16就是现在最常用的unicode版本， 不过在文件里存的还是utf-8，因为utf8省空间

3.在py3中encode,在转码的同时还会把string 变成bytes类型，decode在解码的同时还会把bytes变回string

name='中国'
new_name=name.encode('utf-8')  #对字符串name编码 成二进制字节码
 
print (new_name)
 
输出：
b'\xe4\xb8\xad\xe5\x9b\xbd'

字符串编码成字节码

name='中国'
new_name=name.encode('utf-8')  #对字符串name编码成二进制字节码
 
renew_name=new_name.decode()  #对二进制字节码进行解码
 
print (renew_name)
 
输出：
中国

二进制字节码解码成字符串

上图仅适用于python2

#-*- encoding:utf-8 -*-
 
import sys
 
print(sys.getdefaultencoding())  #打印系统默认编码
 
s='你好'      
 
s_to_unicode=s.decode('utf-8')  #先解码成unicode
 
print(s_to_unicode,type(s_to_unicode))
 
s_to_gbk=s_to_unicode.encode('gbk')  #再编码成gbk
 
print(s_to_gbk)
 
print('你好')
 
#把gbk再转成utf-8
 
gbk_to_utf8=s_to_gbk.decode('gbk').encode('utf-8')
 
print(gbk_to_utf8)

python2.X字符编码示列

#在python3中默认的字符编码是unicode-utf8所以不需要decode了
#-*-coding:gb2312 -*-   #这个也可以去掉    #默认字符集为gb2312
__author__ = 'Alex Li'
 
import sys
print(sys.getdefaultencoding())
 
msg = "我爱北京天安门"
 
#msg_gb2312 = msg.decode("utf-8").encode("gb2312")    #在python2中需要先解码成unicode再编码成gb2312
 
msg_gb2312 = msg.encode("gb2312")   #python3中默认就是unicode utf8,不用再decode,喜大普奔
 
gb2312_to_unicode = msg_gb2312.decode("gb2312")
gb2312_to_utf8 = msg_gb2312.decode("gb2312").encode("utf-8")
 
print(msg)
print(msg_gb2312)
print(gb2312_to_unicode)
print(gb2312_to_utf8)

python3.x字符编码示例

hex()十进制转换为十六进制

hex()二进制转十六进制

#十进制转二进制
number=10
 
to_bin=bin(number)
print(to_bin)
#输出:0b1010
 
#十六进制转二进制
 
number=0xff
 
to_bin=bin(number)
print(to_bin)
#输出:0b11111111

bin()十进制(十六进制)转二进制

#十六进制转十进制
number=0xff
 
to_int=int(number)
print(to_int)
#输出:255
 
#二进制转十进制
number=0b11111111
 
to_int=int(number)
print(to_int)
#输出:255

int()十六进制(二进制)转十进制

name = "python之路"
 
a = bytes(name, encoding='utf-8')
 
print(a)
 
for i in a:
    print(i,bin(i))
 
b = bytes(name, encoding='gbk')
print(b)
for i in b:
    print(i, bin(i))

示例

2、三元运算符

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
 
a,b,c=1,4,6
d= a if a>b else c

三元运算符

3、input和raw_input

# -*-coding:utf-8 -*-
name=raw_input('请输入你的名字：')   #raw_input仅适用于python2.7版本
 
age=input('请输入你的年龄：')
 
print("%s的年龄是%s:"%(name,age))

用户输入input()和raw_input()

# 输入密码时，如果想要不可见，需要利用getpass 模块中的 getpass方法
 
import getpass  #导入getpass模块
 
_username='sunhao'
_password='abc123'
 
username = input("usename:")
 
password = getpass.getpass("password:")
 
if _username==username and password == _password:
    print("Welcome user {name} login...".format(name=_username))
else:
    print("Invalid username or password")

getpass