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  • python中列表分片

    1、基本用法

    >>> test1 = ["aa","bb","cc","dd","ee","ff"]
    >>> type(test1)
    <class 'list'>
    >>> len(test1)
    6
    >>> test1[0:3]   ##  不包含索引为3的元素
    ['aa', 'bb', 'cc']
    >>> test1[2:4]   ## 不包含索引为4的元素
    ['cc', 'dd']>>> test1[:4]
    ['aa', 'bb', 'cc', 'dd']
    >>> test1[2:]
    ['cc', 'dd', 'ee', 'ff']
    >>> test1[:]  ## 完整列表
    ['aa', 'bb', 'cc', 'dd', 'ee', 'ff']
    >>> test1[-3:]   ## 取后三个元素
    ['dd', 'ee', 'ff']

    2、指定步长

    >>> test1 = ["aa","bb","cc","dd","ee","ff","gg","hh","ii","jj"]
    >>> type(test1)
    <class 'list'>
    >>> len(test1)
    10
    >>> test1[0:9:1]
    ['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii']
    >>> test1[0:10:1]
    ['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii', 'jj']
    >>> test1[0:10:2]
    ['aa', 'cc', 'ee', 'gg', 'ii']
    >>> test1[::2]
    ['aa', 'cc', 'ee', 'gg', 'ii']
    >>> test1[0:10:3]
    ['aa', 'dd', 'gg', 'jj']
    >>> test1[::3]
    ['aa', 'dd', 'gg', 'jj']
    >>> test1[::4]
    ['aa', 'ee', 'ii']
    >>> test1[0:6]
    ['aa', 'bb', 'cc', 'dd', 'ee', 'ff']
    >>> test1[0:6:2]
    ['aa', 'cc', 'ee']
    >>> test1[0:6:3]
    ['aa', 'dd']

    3、列表反转

    >>> test1[::1]
    ['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii', 'jj']
    >>> test1[::-1]
    ['jj', 'ii', 'hh', 'gg', 'ff', 'ee', 'dd', 'cc', 'bb', 'aa']
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  • 原文地址:https://www.cnblogs.com/liujiaxin2018/p/14157017.html
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