---恢复内容开始---
正则表达式
简介
正则表达式，就其本质而言，正则表达式（RE) 是一种小型的、高度专业化的
import re
#字符串的处理"abcde".find("b") #返回字符串所处的位置，找不到的话返回-1
"abcde".find("bc")
"abcde".split("b") #以b为分割 字符串
"abcd".replace("ab","ee") #把 ab替换成ee
字符匹配（普通字符，元字符）
普通字符： 大多数字符和字幕都会和自身匹配
import re
re.findall("bin", "adfadfafsdbindfadf") # 在第二个字符串找到第一个字符串，严格匹配，找到会返回，没找到为空
元字符(11个):
. ^ $ * + ? { } [ ] | ( ) \
1. "." 代表除了换行符以外的任何一个换行符. （模糊匹配）
import re
r = re.findall("alex.w", "aaaalexw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
2. "^" 代表匹配是否是此字符开始，字符必须在开头
r = re.findall("^alex.w", "aaaalexkw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/。。。/PycharmProjects/python_fullstack/day9.py
[]
Process finished with exit code 0
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import re
r = re.findall("^alex.w", "alexkw0000")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/stephen/PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
3. “$"符号是匹配尾部
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import re
r = re.findall("alex.w$", "99999alexkw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
4. * 是贪婪匹配 匹配*号之前的一个字符，比如alex* 匹配的是*之前相邻字符 , 0~多次都可以匹配.
如果要匹配多个， *前用括号括起来。
import re
r = re.findall("alex*", "wwwalex")
print(r)
r = re.findall("alex*", "wwwale")
print(r)
r = re.findall("alex*", "wwwalexxxxxxxxxxxxxxxxxxx")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/。。。/PycharmProjects/python_fullstack/day9.py
['alex']
['ale']
['alexxxxxxxxxxxxxxxxxxx']
Process finished with exit code 0
5. “+” 和“*" 类似， 匹配之前的字符，之前字符是1到多次(" * " 是0~多次）.
1 r = re.findall('alex+', "wwwalexxxxxxxxxxxxxx")
2 print(r)
3
4 #输出
5 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
6 ['alexxxxxxxxxxxxxx']
7
8
9
10 r = re.findall('alex+', "wwwale")
11 print(r)
12
13 #输出
14 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
15 []
16
17
18
19 r = re.findall('alex+', "wwwalexxxxxxxxxxxxxxxxxxxxx")
20 print(r)
21
22 #输出
23 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
24 ['alexxxxxxxxxxxxxxxxxxxxx']
6. " ? " 匹配 ‘ ? '之前的0个或者1个字符，无法匹配多个字符
r = re.findall("alex?", "wwwale") #匹配0个"x"
print(r)
r = re.findall('alex?', 'wwwalex') # 匹配1个"x"
print(r)
r = re.findall('alex?', 'wwwalexxxxxx') #无法匹配多个"x"
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['ale']
['alex']
['alex']
Process finished with exit code 0
7. “{}" 匹配指定次数{3}指定匹配3次； {3,5}匹配3～5次（3，4，5)都没问题。
r = re.findall('alex{3}', 'wwwalexxxx') #
print(r)
r = re.findall('alex{3,5}', 'wwwalexx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxxx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxxxxxxxxxxxxx') # 3~5次都可以匹配,最大5次
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexxx']
[]
['alexxx']
['alexxxx']
['alexxxxx']
Process finished with exit code 0
8. “ [] ” 是或的意思，例如'a[bc]d', 可以匹配abd, acd. abcd不行，仅仅匹配1个b/c的字符。
r = re.findall('a[bc]d', 'wwwacd')
print(r)
r = re.findall('a[bc]d', 'wwwabd')
print(r)
r = re.findall('a[bc]d', 'wwwabcd')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['acd']
['abd']
[]
Process finished with exit code 0
". " 在字符集里失去意义，变成了普通字符
r = re.findall('a[.]d', 'wwwaqd')
print(r)
r = re.findall('a[.]d', 'wwwa.d')
print(r)
# 输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
[]
['a.d']
Process finished with exit code 0
在字符集里，仍然有意义的字符,特例是-,^
r = re.findall('[a-z]', 'wwwa.d')
print(r)
r = re.findall('[1-9]', 'www3wa8.d')
print(r)
r = re.findall('[^1-9]', 'www3wa8.d')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['w', 'w', 'w', 'a', 'd']
['3', '8']
['w', 'w', 'w', 'w', 'a', '0', '.', 'd']
Process finished with exit code 0
9. " \ " 反斜杠是最重要的元字符，作用:
(1). 反斜杠后面跟元字符去除元字符的特殊功能；
(2). 后面跟普通字符实现特殊功能。
(3). 引用序号对应的字组所匹配的字符串
r = re.search(r"(alex)(eric)com\2", "alexericcomeric")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
<_sre.SRE_Match object; span=(0, 15), match='alexericcomeric'>
Process finished with exit code 0
\d 匹配任何十进制数； 它相当于类 [ 0-9].
r = re.findall('\d', 'ww3wa8.d0')
print(r)
# 输出
"C:\Program Files\Python35\python.exe" C:/Users/stephen/PycharmProjects/python_fullstack/day9.py
['3', '8', '0']
Process finished with exit code 0
\D 匹配任何非数字字符；她相当于类[^0-9]
\s 匹配任何空白字符；它相当于类[ \t\n\r\f\v]
\S 匹配任何非空白字符；相当于类[^ \t\n\r\f\v]
\w 匹配任何字母数字字符；相当于类[a-zA-Z0-9_]
\W 匹配任何非字母数字字符；相当于类[^a-zA-Z0-9]
\b 匹配一个单词边界，也就是指单词和空格间的位置
---恢复内容结束---
正则表达式
简介
正则表达式，就其本质而言，正则表达式（RE) 是一种小型的、高度专业化的
import re
#字符串的处理"abcde".find("b") #返回字符串所处的位置，找不到的话返回-1
"abcde".find("bc")
"abcde".split("b") #以b为分割 字符串
"abcd".replace("ab","ee") #把 ab替换成ee
字符匹配（普通字符，元字符）
普通字符： 大多数字符和字幕都会和自身匹配
import re
re.findall("bin", "adfadfafsdbindfadf") # 在第二个字符串找到第一个字符串，严格匹配，找到会返回，没找到为空
元字符(11个):
. ^ $ * + ? { } [ ] | ( ) \
1. "." 代表除了换行符以外的任何一个换行符. （模糊匹配）
import re
r = re.findall("alex.w", "aaaalexw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
2. "^" 代表匹配是否是此字符开始，字符必须在开头
r = re.findall("^alex.w", "aaaalexkw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/。。。/PycharmProjects/python_fullstack/day9.py
[]
Process finished with exit code 0
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import re
r = re.findall("^alex.w", "alexkw0000")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/stephen/PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
3. “$"符号是匹配尾部
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import re
r = re.findall("alex.w$", "99999alexkw")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexkw']
Process finished with exit code 0
4. * 是贪婪匹配 匹配*号之前的一个字符，比如alex* 匹配的是*之前相邻字符 , 0~多次都可以匹配.
如果要匹配多个， *前用括号括起来。
import re
r = re.findall("alex*", "wwwalex")
print(r)
r = re.findall("alex*", "wwwale")
print(r)
r = re.findall("alex*", "wwwalexxxxxxxxxxxxxxxxxxx")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/。。。/PycharmProjects/python_fullstack/day9.py
['alex']
['ale']
['alexxxxxxxxxxxxxxxxxxx']
Process finished with exit code 0
5. “+” 和“*" 类似， 匹配之前的字符，之前字符是1到多次(" * " 是0~多次）.
1 r = re.findall('alex+', "wwwalexxxxxxxxxxxxxx")
2 print(r)
3
4 #输出
5 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
6 ['alexxxxxxxxxxxxxx']
7
8
9
10 r = re.findall('alex+', "wwwale")
11 print(r)
12
13 #输出
14 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
15 []
16
17
18
19 r = re.findall('alex+', "wwwalexxxxxxxxxxxxxxxxxxxxx")
20 print(r)
21
22 #输出
23 "C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
24 ['alexxxxxxxxxxxxxxxxxxxxx']
6. " ? " 匹配 ‘ ? '之前的0个或者1个字符，无法匹配多个字符
r = re.findall("alex?", "wwwale") #匹配0个"x"
print(r)
r = re.findall('alex?', 'wwwalex') # 匹配1个"x"
print(r)
r = re.findall('alex?', 'wwwalexxxxxx') #无法匹配多个"x"
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['ale']
['alex']
['alex']
Process finished with exit code 0
7. “{}" 匹配指定次数{3}指定匹配3次； {3,5}匹配3～5次（3，4，5)都没问题。
r = re.findall('alex{3}', 'wwwalexxxx') #
print(r)
r = re.findall('alex{3,5}', 'wwwalexx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxxx') # 3~5次都可以匹配,最大5次
print(r)
r = re.findall('alex{3,5}', 'wwwalexxxxxxxxxxxxxx') # 3~5次都可以匹配,最大5次
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['alexxx']
[]
['alexxx']
['alexxxx']
['alexxxxx']
Process finished with exit code 0
8. “ [] ” 是或的意思，例如'a[bc]d', 可以匹配abd, acd. abcd不行，仅仅匹配1个b/c的字符。
r = re.findall('a[bc]d', 'wwwacd')
print(r)
r = re.findall('a[bc]d', 'wwwabd')
print(r)
r = re.findall('a[bc]d', 'wwwabcd')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['acd']
['abd']
[]
Process finished with exit code 0
". " 在字符集里失去意义，变成了普通字符
r = re.findall('a[.]d', 'wwwaqd')
print(r)
r = re.findall('a[.]d', 'wwwa.d')
print(r)
# 输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
[]
['a.d']
Process finished with exit code 0
在字符集里，仍然有意义的字符,特例是-,^ \d
r = re.findall('[a-z]', 'wwwa.d')
print(r)
r = re.findall('[1-9]', 'www3wa8.d')
print(r)
r = re.findall('[^1-9]', 'www3wa8.d')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['w', 'w', 'w', 'a', 'd']
['3', '8']
['w', 'w', 'w', 'w', 'a', '0', '.', 'd']
Process finished with exit code 0
r = re.findall('[\d]', ' ww3 wa8.d0')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/stephen/PycharmProjects/python_fullstack/day9.py
[' ']
9. " \ " 反斜杠是最重要的元字符，作用:
(1). 反斜杠后面跟元字符去除元字符的特殊功能；
(2). 后面跟普通字符实现特殊功能。
(3). 引用序号对应的字组所匹配的字符串
r = re.search(r"(alex)(eric)com\2", "alexericcomeric") # \2 代表第二个group(2) ---> "eric"; group(1)代之alex,group(2)代表"eric"
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
<_sre.SRE_Match object; span=(0, 15), match='alexericcomeric'>
Process finished with exit code 0
\d 匹配任何十进制数； 它相当于类 [ 0-9].
r = re.findall('\d', 'ww3wa8.d0') # 匹配1个数字
print(r)
r = re.findall('\d\d', 'ww23wa8.d0') #匹配2个
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['3', '8', '0']
['23']
Process finished with exit code 0
\D 匹配任何非数字字符；她相当于类[^0-9]
r = re.findall('\D', 'ww3wa8.d0') # 匹配1非数字
print(r)
r = re.findall('\D\D', 'ww3wa8.d0') # 匹配2非数字
print(r)
# 输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['w', 'w', 'w', 'a', '.', 'd']
['ww', 'wa', '.d']
Process finished with exit code 0
\s 匹配任何空白字符；它相当于类[ \t\n\r\f\v]
r = re.findall('\s', 'ww3 wa8.d0')
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
[' ']
\S 匹配任何非空白字符；相当于类[^ \t\n\r\f\v]
\w 匹配任何字母数字字符；相当于类[a-zA-Z0-9_]
r = re.findall('\w', 'ww3wa8.d0') # 匹配任意字母数字
print(r)
r = re.findall('\w\w', 'ww3wa8.d0') # 匹配2个任意字母数字
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/.../PycharmProjects/python_fullstack/day9.py
['w', 'w', '3', 'w', 'a', '8', 'd', '0']
['ww', '3w', 'a8', 'd0']
Process finished with exit code 0
\W 匹配任何非字母数字字符；相当于类[^a-zA-Z0-9]
\b 匹配一个单词边界，也就是指单词和空格间的位置
r = re.findall(r"\bads\b", "abc bcd sf!ads!fasdf ads asfasfasdfasdfasdf")
print(r)
#输出
"C:\Program Files\Python35\python.exe" C:/Users/stephen/PycharmProjects/python_fullstack/day9.py
['ads', 'ads']
Process finished with exit code 0