一.基本数据类型
整数:int
字符串:str(注:\t等于一个tab键)
布尔值: bool
列表:list
列表用[]
元祖:tuple
元祖用()
字典:dict
注:所有的数据类型都存在想对应的类列里,元祖和列表功能一样,列表可以修改,元祖不能修改。
二.列表所有数据类型:
基本操作:
索引,切片,长度,包含,循环
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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 """
(T.count(价值) - >整数,返回值的出现次数)
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.
"""
(T。指数(价值,[开始,[不要]]) - >整数,返回第一索引值。提出了ValueError如果不存在的价值。)
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
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三.所有元祖数据类型举例
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#count 用于计算元素出现的个数
name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
print (name_tuple.count( 'zhangyanlin' ))
#index获取指定元素的指定位置
name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
print (name_tuple.index( 'zhangyanlin' ))
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四.索引
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name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
print (name_tuple[ 1 ])
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五.切片
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#取出第一位到最后一位减1的元素
name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
print (name_tuple[ 0 : len (name_tuple) - 1 ])
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六.总长度len
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#取出最后一位减1的元素
name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
print (name_tuple[ len (name_tuple) - 1 ])
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七.for循环
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name_tuple = ( "zhangyanlin" , "suoning" , "nick" )
for i in name_tuple:
print (i)
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那么使用 tuple 有什么好处呢?
Tuple 比 list 操作速度快。如果您定义了一个值的常量集,并且唯一要用它做的是不断地遍历它,请使用 tuple 代替 list。
如果对不需要修改的数据进行 “写保护”,可以使代码更安全。使用 tuple 而不是 list 如同拥有一个隐含的 assert 语句,说明这一数据是常量。如果必须要改变这些值,则需要执行 tuple 到 list 的转换 (需要使用一个特殊的函数)。
还记得我说过 dictionary keys 可以是字符串,整数和 “其它几种类型”吗?Tuples 就是这些类型之一。Tuples 可以在 dictionary 中被用做 key,但是 list 不行。实际上,事情要比这更复杂。Dictionary key 必须是不可变的。Tuple 本身是不可改变的,但是如果您有一个 list 的 tuple,那就认为是可变的了,用做 dictionary key 就是不安全的。只有字符串、整数或其它对 dictionary 安全的 tuple 才可以用作 dictionary key。
Tuples 可以用在字符串格式化中,我们会很快看到。