Python正则表达式语法
单个字符匹配
| 字符 | 匹配 |
| . | 匹配任意字符（除了\n） |
| [...] | 匹配字符集 |
| \d/\D | 匹配数字/非数字 |
| \s/\S | 匹配空白/非空白字符 |
| \w/\W | 匹配单词字符[a-zA-A0-9] |
In [8]: ma = re.match(r'.','b') In [9]: ma.gro ma.group ma.groupdict ma.groups In [9]: ma.group() Out[9]: 'b' In [10]: ma = re.match(r'.','0') In [11]: ma.grou ma.group ma.groupdict ma.groups In [11]: ma.group() Out[11]: '0' In [12]: clear In [13]: ma = re.match(r'{.}','{a}') In [14]: ma.group() Out[14]: '{a}' In [15]: ma = re.match(r'{.}','{0}') In [16]: ma.grou ma.group ma.groupdict ma.groups In [16]: ma.group() Out[16]: '{0}' In [17]: ma = re.match(r'{..}','{01}') In [18]: ma.group() Out[18]: '{01}' In [19]: ma = re.match(r'{[abc]}','{a}') In [20]: ma.group() Out[20]: '{a}' In [21]: ma = re.match(r'{[a-z]}','{d}') In [22]: ma.group() Out[22]: '{d}' In [23]: ma = re.match(r'{[a-zA-Z]}','{A}') In [24]: ma.group() Out[24]: '{A}' In [25]: ma = re.match(r'{[a-zA-Z0-9]}','{0}') In [26]: ma.group() Out[26]: '{0}' In [27]: ma = re.match(r'{[\w]}','{ }') In [28]: ma In [29]: ma = re.match(r'{[\W]}','{ }') In [30]: ma Out[30]: <_sre.SRE_Match object; span=(0, 3), match='{ }'> In [31]: ma.group() Out[31]: '{ }' In [32]: ma = re.match(r'{[\W]}','{9}') In [33]: ma.group() --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-33-7c62fc675aee> in <module>() ----> 1 ma.group() AttributeError: 'NoneType' object has no attribute 'group' In [34]: ma In [35]: ma = re.match(r'[[\w]]','[a]') In [36]: ma In [37]: ma = re.match(r'\[[\w]\]','[a]') In [38]: ma.group() Out[38]: '[a]' In [39]: ma = re.match(r'\[[\w]\]','[0]') In [40]: ma.group() Out[40]: '[0]' In [41]:
多个字符匹配
| 字符 | 匹配 |
| * | 匹配前一个字符0次或者无限次 |
| + | 匹配前一个字符1次或者无限次 |
| ? | 匹配前一个字符0次或者1次 |
| {m}/{m,n} | 匹配前一个字符m次或者n次 |
| *?/+?/?? | 匹配模式变为非贪婪（尽可能少匹配字符） |
In [1]: import re In [2]: ma = re.match(r'[A-Z][a-z]','Aa') In [3]: ma.grou ma.group ma.groupdict ma.groups In [3]: ma.group() Out[3]: 'Aa' In [4]: ma = re.match(r'[A-Z][a-z]','A') In [6]: ma In [8]: In [8]: ma = re.match(r'[A-Z][a-z]*','A') In [9]: ma Out[9]: <_sre.SRE_Match object; span=(0, 1), match='A'> In [10]: ma.group() Out[10]: 'A' In [12]: ma = re.match(r'[A-Z][a-z]*','Asdsdwqass') In [14]: ma. ma.end ma.group ma.lastgroup ma.re ma.start ma.endpos ma.groupdict ma.lastindex ma.regs ma.string ma.expand ma.groups ma.pos ma.span In [14]: ma.group() Out[14]: 'Asdsdwqass' In [15]: ma = re.match(r'[A-Z][a-z]*','1Asdsdwqass') In [16]: ma In [17]: ma = re.match(r'[A-Z][a-z]*','Asd1sdwqass') In [18]: ma.group() Out[18]: 'Asd' In [19]: ma = re.match(r'[_a-zA-Z]+[_\w]*','10') In [20]: ma In [21]: ma = re.match(r'[_a-zA-Z]+[_\w]*','_ht11') In [22]: ma.group() Out[22]: '_ht11' In [23]: ma = re.match(r'[1-9]?[0-9]','99') In [24]: ma.group() Out[24]: '99' In [25]: ma = re.match(r'[1-9]?[0-9]','90') In [26]: ma.group() Out[26]: '90' In [27]: ma = re.match(r'[1-9]?[0-9]','9') In [28]: ma.group() Out[28]: '9' In [29]: ma = re.match(r'[1-9]?[0-9]','0') In [30]: ma.group() Out[30]: '0' In [31]: ma = re.match(r'[1-9]?[0-9]','09') In [32]: ma.group() Out[32]: '0' In [33]: ma = re.match(r'[[a-zA-Z0-9]{6}','abc123') In [34]: ma.group() Out[34]: 'abc123' In [35]: ma = re.match(r'[[a-zA-Z0-9]{6}','abc1234') In [36]: ma.group() Out[36]: 'abc123' In [37]: ma = re.match(r'[[a-zA-Z0-9]{6}','abc1__') In [38]: ma In [39]: ma = re.match(r'[[a-zA-Z0-9]{6}@163.com','abc123@163.com') In [40]: ma.group() Out[40]: 'abc123@163.com' In [41]: ma = re.match(r'[[a-zA-Z0-9]{6,10}@163.com','abc1234@163.com') In [42]: ma.grou ma.group ma.groupdict ma.groups In [42]: ma.group() Out[42]: 'abc1234@163.com' In [43]: ma = re.match(r'[0-9][a-z]*?','1bc') In [44]: ma.group() Out[44]: '1' In [45]: ma = re.match(r'[0-9][a-z]*','1bc') In [46]: ma.group() Out[46]: '1bc'
边界匹配
| 字符 | 匹配 |
| ^ | 匹配字符串开头 |
| $ | 匹配字符串结尾 |
| \A/\Z | 指定的字符串匹必须出现在开头/结尾 |
In [48]: ma = re.match(r'[[a-zA-Z0-9]{6,10}@163.com','abc1234@163.comabc') In [49]: ma.group() Out[49]: 'abc1234@163.com' In [50]: ma = re.match(r'[[a-zA-Z0-9]{6,10}@163.com$','abc1234@163.comabc') In [51]: ma In [52]: ma = re.match(r'^[[a-zA-Z0-9]{6,10}@163.com$','abc1234@163.com') In [53]: ma.group() Out[53]: 'abc1234@163.com' In [54]: ma = re.match(r'\Aimooc[\w]*','imoocpython') In [55]: ma.group() Out[55]: 'imoocpython' In [56]: ma = re.match(r'\Aimooc[\w]*','iimooc') In [57]: ma.group() --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-57-7c62fc675aee> in <module>() ----> 1 ma.group() AttributeError: 'NoneType' object has no attribute 'group'
分组匹配
| 字符 | 匹配 |
| | | 匹配左右任意一个表达式 |
| (a,b) | 括号中表达式作为一个分组 |
| \<number> | 引用编号为num的分组匹配到的字符串 |
| (?P<name>) | 分组起一个别名 |
| (?P=name) | 引用别名为name的分组匹配字符串 |
In [59]: ma = re.match(r'abc|d','abc') In [60]: ma.group() Out[60]: 'abc' In [61]: ma = re.match(r'abc|d','d') In [62]: ma.group() Out[62]: 'd' In [63]: ma = re.match(r'[1-9]?\d$','9') In [64]: ma.group() Out[64]: '9' In [65]: ma = re.match(r'[1-9]?\d$','99') In [66]: ma.group() Out[66]: '99' In [67]: ma = re.match(r'[1-9]?\d$','09') In [68]: ma In [69]: ma = re.match(r'[1-9]?\d$','100') In [70]: ma.group() --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-70-7c62fc675aee> in <module>() ----> 1 ma.group() AttributeError: 'NoneType' object has no attribute 'group' In [71]: ma = re.match(r'[1-9]?\d$|100','100') In [72]: ma.group() Out[72]: '100' In [73]: ma = re.match(r'[1-9]?\d$|100','99') In [74]: ma.group() Out[74]: '99' In [75]: ma = re.match(r'[\w]{4,6}@163.com','imooc@163.com') In [76]: ma.group() Out[76]: 'imooc@163.com' In [77]: ma = re.match(r'[\w]{4,6}@(163,123).com','imooc@163.com') In [78]: ma = re.match(r'[\w]{4,6}@(163,123).com','imooc@123.com') In [79]: ma.group() --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-79-7c62fc675aee> in <module>() ----> 1 ma.group() AttributeError: 'NoneType' object has no attribute 'group' In [80]: ma = re.match(r'[\w]{4,6}@(163|123).com','imooc@123.com') In [81]: ma.group() Out[81]: 'imooc@123.com' In [82]: ma = re.match(r'<[\w]+>','<book>') In [83]: ma.group() Out[83]: '<book>' In [84]: ma = re.match(r'<([\w]+>)','<book>') In [85]: ma.group() Out[85]: '<book>' In [86]: ma = re.match(r'<([\w]+>)\1','<book>') In [87]: ma.groups() --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-87-f4e4ca66607d> in <module>() ----> 1 ma.groups() AttributeError: 'NoneType' object has no attribute 'groups' In [88]: ma = re.match(r'<([\w]+>)\1','<book>book>') In [89]: ma.groups() Out[89]: ('book>',) In [90]: ma.group() Out[90]: '<book>book>' In [91]: ma = re.match(r'<([\w]+>\1','<book>book>') In [3]: ma = re.match(r'<([\w]+>)[\w]+</\1','<book>python</book>') In [4]: ma.group() Out[4]: '<book>python</book>' In [5]: ma = re.match(r'<([\w]+>)[\w]+</\1','<book>python</book1>') In [6]: ma In [9]: ma = re.match(r'<(?P<mark>[\w]+>)[\w]+</(?P=mark)','<book>python</book>') In [10]: ma.group() Out[10]: '<book>python</book>'
