python 正则表达式

Posted 2021-03-18 A running snail,little step ev

基本语法

 

# 1. 一般字符: 匹配字符的本身
print(re.match("abc","abcdefg"))
print("abc" in "abcdefg")

# 2　【.】　－－匹配一个除\\n 外所有的字符
# 需求: 三个字母,第一个是a
print(re.match("^a..$","a35"))

# 3　【\\】　－－转义字符
print(re.match("a\\...","a.1#"))
print(re.match("a[.]..","a.123"))
print(re.match("a[.]..$","a.1#asdfasdf"))
# 4　【】　－－字符集中的任意一个字符
print(re.match("^a[bdc]e$","abe"))
print(re.match("^a[bdc]e$","ade"))
print(re.match("^a[bdc]e$","ace"))

# 5　开头: ^ 结尾: $  --- 完全匹配
print(re.match("^a[bdc]f$","acf"))

<re.Match object; span=(0, 3), match=\'abc\'>
True
<re.Match object; span=(0, 3), match=\'a35\'>
<re.Match object; span=(0, 4), match=\'a.1#\'>
<re.Match object; span=(0, 4), match=\'a.12\'>
None
<re.Match object; span=(0, 3), match=\'abe\'>
<re.Match object; span=(0, 3), match=\'ade\'>
<re.Match object; span=(0, 3), match=\'ace\'>
<re.Match object; span=(0, 3), match=\'acf\'>

print(re.findall("\\^\\d{3}","^123dafd^888safd"))
#2　【.】　－－匹配一个除\\n 外所有的字符
print(re.findall("a.{3}","^123d adfd a3434 afd^888safd"))

[\'^123\', \'^888\']
[\'adfd\', \'a343\', \'afd^\']

#2　【.】　－－匹配\\ 这个字符
print(re.findall("\\\\\\\\X","\\Xdfdfd \\Xadfd \\Xa3434 \\xafd^888safd"))

print(re.findall("\\\\b","\\Xdfdfd \\Xadfd \\Xa3434 \\xafd^888safd"))
#为了避免困扰,建议写正则时加R/r
print(re.findall(r"\\\\b","\\Xdfdfd \\Xadfd \\Xa3434 \\xafd^888safd"))
print(re.findall(r"\\\\","\\Xdfdfd \\Xadfd \\Xa3434 \\xafd^888safd"))

[\'\\\\X\', \'\\\\X\', \'\\\\X\']
[\'\', \'\', \'\', \'\', \'\', \'\', \'\', \'\', \'\', \'\']
[]
[\'\\\\\', \'\\\\\', \'\\\\\']

 

 

print(re.findall(R"\\D\\s{2}\\w","a  4 fadfsdfasd adfasdf  _f"))
#匹配a-f开头 不区分大小写,后面三个小写字每句,后面以偶数结尾
print(re.findall(R"[a-zA-Z][a-z]{3}[02468]","asdfd2  4 fadfsdfasd6 adfasdf8  _f"))

[\'a  4\', \'f  _\']
[\'sdfd2\', \'fasd6\', \'asdf8\']

 

print(re.findall(r"na[a-z]*e","my name is nae  date nadwsdfe nadwsdfddde nadwsdfddfdfddsdde"))
print(re.findall(r"na[a-z]+e","my name is nae  date nadwsdfe nadwsdfddde nadwsdfddfdfddsdde"))
print(re.findall(r"na[a-z]?e","my name is nae  date nadwsdfe nadwsdfddde nadwsdfddfdfddsdde"))
print(re.findall(r"na[a-z]{5}e","my name is nae  date nadwsdfe nadwsdfddde nadwsdfddfdfddsdde"))
print(re.match(r"(\\d{14}[0-9X])|(\\d{17}[0-9X])","411111111111111111"))
print(re.findall(r"na[a-z]{5,10}e","my name is nae  date nadwsdfe nadwsdfddde"))
print(re.findall(r"na[a-z]{5,}e","my name is nae  date nadwsdfe nadwsdfddde nadwsdfddfdfddsdde"))

[\'name\', \'nae\', \'nadwsdfe\', \'nadwsdfddde\', \'nadwsdfddfdfddsdde\']
[\'name\', \'nadwsdfe\', \'nadwsdfddde\', \'nadwsdfddfdfddsdde\']
[\'name\', \'nae\']
[\'nadwsdfe\']
<re.Match object; span=(0, 15), match=\'411111111111111\'>
[\'nadwsdfe\', \'nadwsdfddde\']
[\'nadwsdfe\', \'nadwsdfddde\', \'nadwsdfddfdfddsdde\']

 

import  re
match_result = re.finditer(R"\\b([a-z])([a-z])[a-z]\\2\\1\\b","fdafd abcba ytgty asdsa")
match_list=[]
for i in match_result:
    match_list.append(i.group(0))
print(match_list)

print(re.findall(R"\\b(?P<number01>[a-z])(?P<number02>[a-z])[a-z](?P=number02)(?P=number01)\\b","fdafd abcba ytgty asdsa"))

[\'abcba\', \'ytgty\', \'asdsa\']
[(\'a\', \'b\'), (\'y\', \'t\'), (\'a\', \'s\')]

print(re.findall(R"\\b(?<=name=)[a-z]+\\b","fdafd name=abcba name=ytgty name=asdsa"))

[\'abcba\', \'ytgty\', \'asdsa\']