python 元组

Posted 2021-01-03 zjl-001

1.创建元组

>>> tuple = (1,2,3,4,5)
>>> tuple
(1, 2, 3, 4, 5)

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2.访问元组

>>> tuple = (1,2,3,4,5)
>>> tuple
(1, 2, 3, 4, 5)
>>> tuple[1:3]
(2, 3)

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3.注意：如果创建的元祖只有一个元素，请在元素后面加上逗号

>>> tup = ()
>>> tup1 = (1)
>>> tup2 = (1,)
>>> type(tup)
<class ‘tuple‘>
>>> type(tup1)
<class ‘int‘>
>>> type(tup2)
<class ‘tuple‘>

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4.元组修改

4.1：元组内元素不可修改

>>> tup = (1,‘zc‘,‘cc‘,‘2‘,‘gg‘)
>>> tup[1] = 2
Traceback (most recent call last):
  File "<pyshell#103>", line 1, in <module>
    tup[1] = 2
TypeError: ‘tuple‘ object does not support item assignment

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4.2：只可删除整个元组

>>> tup = (1,‘zc‘,‘cc‘,‘2‘,‘gg‘)
>>> del tup[1]
Traceback (most recent call last):
  File "<pyshell#105>", line 1, in <module>
    del tup[1]
TypeError: ‘tuple‘ object doesn‘t support item deletion
>>> del tup
>>> tup
Traceback (most recent call last):
  File "<pyshell#107>", line 1, in <module>
    tup
NameError: name ‘tup‘ is not defined

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4.3：修改元组内部，须切片拷贝

>>> temp = (‘小鸡‘,‘小猪‘,‘小鸭‘,‘小狗‘)
>>> temp[:2] + (‘通过切片增加一个元素‘,) + temp[2:]
(‘小鸡‘, ‘小猪‘, ‘通过切片增加一个元素‘, ‘小鸭‘, ‘小狗‘)

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>>> temp = (‘小鸡‘,‘小猪‘,‘小鸭‘,‘小狗‘)
>>> temp[:1] + temp[2:]
(‘小鸡‘, ‘小鸭‘, ‘小狗‘)

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4.4：用del删除整个元组

>>> temp = (‘小鸡‘,‘小猪‘,‘小鸭‘,‘小狗‘)
>>> del temp
>>> temp
Traceback (most recent call last):
  File "<pyshell#123>", line 1, in <module>
    temp
NameError: name ‘temp‘ is not defined

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5.元组的方法

5.1：count  统计元素在列表中出现的次数

>>> temp = (‘小鸡‘,‘小猪‘,‘小鸭‘,‘小狗‘,‘小狗‘)
>>> temp.count(‘小狗‘)
2
>>> temp.count(‘小鸡‘)
1

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5.2：index()   查到元素在列表中的位置

>>> temp = (‘小鸡‘,‘小猪‘,‘小鸭‘,‘小狗‘,‘小狗‘)
>>> temp.index(‘小猪‘)
1

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