Python正则表达式之：(?P<name>) (?P=name) 及 \g<name> 三者的使用区别

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import re   s="2023-12-23 14:34:56|liming|20230789" parren="(?P<time>^\d+-\d+-\d+\s\d+:\d+:\d+)\|(?P<name>[\w]+)\|(?P<number>\d+)$" g=re.search(parren,s) >>> g.groupdict() {'time': '2023-12-23 14:34:56', 'name': 'liming', 'number': '20230789'} >>> g.group('time') '2023-12-23 14:34:56' >>> g.group('name') 'liming' >>> g.group('number') '20230789'

　

 样例2

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astr1 = 'AAbb aabb' astr2 = 'aabb aabb' astr3 = 'aabb ccbb'    for s in astr1,astr2,astr3:     result = re.match(r'(?i)(?P<pattern>[\w]+) (?P=pattern)',s)     if result != None:         print('{} match result is {}'.format(s,result.group()))     else:         print('{} match Nothing'.format(s))    #AAbb aabb match result is AAbb aabb #aabb aabb match result is aabb aabb #aabb ccbb match Nothing   #可以看到(?P<pattern>)可以用来标记一些模糊的模式，然后在同一个正则表达式中，我们可以通过(?P=pattern)来复用之前的内容，这就是它们两个的用法区别，一个用于标记，一个用于在同一个正则表达式中复用，<br>特别提醒：同一个正则表达式

　样例3

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astr = 'aabb aacc aadd' result = re.sub(r'(?i)aa(?P<pattern>[\w]+)',r'bb\g<pattern>',astr) print('{} has been substituted to {}'.format(astr,result))    #aabb aacc aadd has been substituted to bbbb bbcc bbdd<br><br>#不同的表达式中复用