元组类型内置方法
tuple(掌握)
元组是不可变的列表,即元组的值不可更改,因此元组一般只用于只存不取的需求。也因此元组可以被列表取代掉,所以元组相比较列表使用的很少。元组相比较列表的优点为:列表的值修改后,列表的结构将会发生改变,而元组只需要存储,因此列表在某种程度上而言需要占用更多的内存。但是目前工业上内存已经不是问题了,所以工业上元组一般不会使用。
用途:多个装备、多个爱好、多门课程,甚至是多个女朋友
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定义:在()内可以有多个任意类型的值,逗号分隔元素
my_play_game = ('lol', 'cf', 'qq') print(f"my_play_game: {my_play_game}") my_play_game: ('lol', 'cf', 'qq')
name_str = ('egon') # ()只是普通包含的意思 name_tuple = ('egon',) print(f"type(name_str): {type(name_str)}") print(f"type(name_tuple): {type(name_tuple)}") type(name_str): <class 'tuple'> type(name_tuple): <class 'tuple'>
常用操作+内置方法:常用操作和内置方法:
优先掌握
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索引取值
name_tuple = ('lol','dnf','cf','qq') print(f'name_list:{name_list[0]}') name_tuple:lol
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切片(顾头不顾尾,步长)
name_tuple = ('lol','dnf','cf','qq') print(f"name_list[1:3:2]:{name_list[1:3:2]}") name_tuple[1:3]:('dnf',)
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长度len
name_tuple = ('lol','dnf','cf','qq') print(f'len(name_tuple):{len(name_tuple)}') len(name_tuple):4
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成员运算in和not in
name_tuple = ('lol','dnf','cf','qq') print(f"dnf in name_tuple:{'dnf' in name_tuple}") print(f"dnf not in name_tuple:{'dnf'not in name_tuple}") dnf in name_tuple:True dnf not in name_tuple:False
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循环
name_tuple = ('lol','dnf','cf','qq') for i in name_tuple : print(f'name_tple:{i}') name_tple:lol name_tple:dnf name_tple:cf name_tple:qq
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count 获取指定元素的值
name_tuple = ('lol','dnf','cf','qq') print(f"name_tuple.count('cf'):{name_tuple.count('cf')}") name_tuple.count('cf'):1
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index 获取指定元素的索引值
name_tuple = ('lol','dnf','cf','qq') print(f"name_tuple.index('qq'):{name_tuple.index('qq')}") name_tuple.index('qq'):3
存一个值or多个值:一个值
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有序or无序:有序
name_tuple = ('jin',) print(f'id(name_tuple):{id(name_tuple)}') id(name_tuple):30399008
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可变or不可变:不可变数据类型
n = ['a','b','c'] print(f'id(n[0]):{id(n[0])}') n[0] = 'd' print(f'id(n[0]):{id(n[0])}') id(n[0]):31019392 id(n[0]):30591272
列表可变的原因是:索引所对应的值的内存地址是可以改变的
元组不可变得原因是:索引所对应的值的内存地址是不可以改变的,或者反过来说,只要索引对应值的内存地址没有改变,那么元组是始终没有改变的。
n1 = ('a','b','c',['d','e','f']) print(f'id(n1[0]):{id(n1[0])}') print(f'id(n1[0]):{id(n1[1])}') print(f'id(n1[0]):{id(n1[2])}') print(f'id(n1[0]):{id(n1[3])}') n1[3][0] = 'D' print(f'n1[3][0]:{n1[3][0]}') print(f'id(n1[3]:{id(n1[3])}') print(f'n1:{n1}') id(n1[0]):6574464 id(n1[0]):6556336 id(n1[0]):6144888 id(n1[0]):31868872 n1[3][0]:D id(n1[3]:31868872 n1:('a', 'b', 'c', ['D', 'e', 'f'])