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  • python高级特性-列表生成

     概述

    [x *x for x in range(1,11)]
    [k+'='+v for k,v in d.items()]
    [s.lower() for s in L]

    详解

    1.单层迭代

    >>> [x *x for x in range(1,11)]
    [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
    >>> [x*x for x in range(1,11) if x%2 ==0]
    [4, 16, 36, 64, 100]

    2.双层for循环

    >>> [m+n for m in 'abc' for n in 'cde']
    ['ac', 'ad', 'ae', 'bc', 'bd', 'be', 'cc', 'cd', 'ce']

    3.列出文件和目录名

    >>> import os
    >>> [d for d in os.listdir('.')]
    ['X_face1.3.2_20170505_qywp', 'X_solr2.0.1_20170607', 'X_media_20170524', 'install.log', 'X_LK_client1.0_20151031', '.mysql_history', 'X_LK_server1.3.0_20160906', 'X_sea2.1.0.20170622_qywp.tar.gz', 'X_fish2.3.16_170414_18110A.tar.gz', '.config', 'anaconda-ks.cfg', 'X_LK_client1.0_20151031.tar.gz', 'X_fish2.3.16_170414_18110', 'X_face1.3.2_20170505_qywp.tar.gz', 'X_LK_server1.3.0_20160906.tar.gz', 'X_sea2.1.0.20170622_qywp', '.tcshrc', '.cshrc', 'X_media_20170524.tar.gz', '.bashrc', '.bash_logout', 'xefxbcx81', '.bash_history', 'install.log.syslog', '.bash_profile', 'X_solr2.0.1_20170607.tar.gz', '.viminfo']

    4.字典迭代

    >>> d = {'x': 'A', 'y': 'B', 'z': 'C' }
    >>> for k,v in d.items():
    ...      print k,'=',v
    ... 
    y = B
    x = A
    z = C

     >>> d = {'x': 'A', 'y': 'B', 'z': 'C' }
     >>> [k+'='+v for k,v in d.items()]
     ['y=B', 'x=A', 'z=C']

    5.所以字符串变成小写

    >>> L = ['Hello', 'World', 'IBM', 'Apple']
    >>> [s.lower() for s in L]
    ['hello', 'world', 'ibm', 'apple']
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  • 原文地址:https://www.cnblogs.com/yaohong/p/7483779.html
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