python 正则表达式

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']