Python-正则表达式的元字符

import re

print("--------------匹配单个字符与数字--------------")
'''
r
.  匹配除换行符以外的任意字符
[0123456789]  []是字符集合,表示匹配方括号中所包含的任意一个字符
[sunck]       匹配's','u','n','c','k'中任意一个字符
[a-z]         匹配任意小写字母
[A-Z]         匹配任意大写字母
[0-9]         匹配任意数字,类似[0123456789]
[0-9a-zA-Z]   匹配任意的数字和字母(注意之间没有空格)
[0-9a-zA-Z_]  匹配任意的数字、字母、下划线(注意之间没有空格)
[^sunck]      匹配除了sunck这几个字母以外的所有字符
^称为脱字符,表示不匹配集合中的字符
[^0-9]        匹配所有的非数字字符
\d            匹配数字,效果[0-9]
\D            匹配非数字字符,效果同[^0-9]
\w            匹配数字,字母和下划线,效果同[0-9a-zA-Z_]
\W            匹配非数字,字母和下划线,效果同[^0-9a-zA-Z_]
\s            匹配任意的空白符(格,换行,回车,换页,制表),效果同
              [ \f\n\r\t]
\S            匹配任意的非空白符,效果同[^ \f\n\r\t]
'''

print(re.search(".","sunck is a good man "))
print(re.search("[0123456789]","sunck is a good man 3"))
print(re.search("[sunck]","sunck is a good man 3"))
print(re.findall("[\d]","sunck is a good man 3"))
print(re.search("\D","sunck is a good man 3"))
print(re.search("\w","_sunck is a good man 3"))
print(re.findall("\d","_sunck is 6a go80d man 3" ))


print("-------------------锚字符(边界字符)-------------------")
'''
^        行首匹配,和[]里的^不是一个意思
$        行尾匹配  

\A       匹配字符串开始,它和^的区别是,\A只匹配整个字符串的开头,即使
         在re.M模式下也不会匹配他行的行首
\Z       匹配字符串的结束,它和$的区别是,\Z只匹配整个字符串的结束,即使
         在re.M模式下也不会匹配他行的行尾
         
\b       匹配一个单词的边界,也就是指单词和空格间的位置
         'er\b'可以匹配never,不能匹配nerve
\B       匹配非单词边界
'''

print(re.search("^sunck","sunck si a good man"))
print(re.search("sunck$","sunck si a good man"))
print(re.search("man$","sunck si a good man"))
print(re.search("^man$","sunck si a good man"))

print(re.search("^sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("^sunck","sunck si a good man\nsunck is a nice man",re.M))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man",re.M))

print(re.search(r"er\b","never"))
print(re.search(r"er\b","nerve"))
print(re.search(r"er\B","never"))
print(re.search(r"er\B","nerve"))





print("-------------------------匹配多个字符-------------------------")

'''
说明:下方的x,y,z,n均为假设的普通字符,不是正则表达式的元字符(xyz)   
      匹配小括号内的xyz(作为一个整体去匹配)
x?    匹配0个或者任意1个x
x*    匹配0个或者任意多个x(.*表示匹配0个或者任意多个字符(换行符除外))
x+    匹配至少一个x
x{n}  匹配确定的n个x(n是一个非负整数)
x{n,} 匹配至少n个x
x{n,m}匹配至少n个最多m个。注意:n <= m
x|y   |表示或,匹配的是x或y
'''
print(re.findall(r"(sunck)","sunck is a good man ,sunck is a nice man "))
print(re.findall(r"0?","sunck is a good man ,sunck is a nice man "))

print(re.findall(r"a?","aaa"))   # 非贪婪匹配(尽可能少的匹配)
print(re.findall(r"a*","aaabaa")) # 贪婪匹配(尽可能多的匹配)
print(re.findall(r".*","aaabaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaabaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3}","aa"))
print(re.findall(r"a{3}","aaaa"))
print(re.findall(r"a{3}","aaaaa"))
print(re.findall(r"a{3}","aaabaa"))

print(re.findall(r"a{3,}","aaaaa"))
print(re.findall(r"a{3,}","aaa"))
print(re.findall(r"a{3,}","aa"))
print(re.findall(r"a{3,}","aaaaabaaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3,6}","aaaaabaaa"))

print(re.findall(r"((s|S)unck)","sunck--Sunck"))
print(re.findall(r"((s|S)unck)","sunck--SuNck"))

# 需求,提取sunck……man,
str = "sunck is a good man!sunck is a nice man!sunck is a very handsome man "
print(re.findall(r"^sunck.*man",str))
print(re.findall(r"^sunck.*man$",str))

print("-------------------特殊-------------------------")
'''
*?  +?  x?   最小匹配   通常都是尽快可能多的匹配,可以用这种方式解决贪婪匹配
(?:x)        类似(xyz),但不表示一个组
'''
# 注释:  /* part1 */  /*  part2  /*
print(re.findall(r"//*.*/*/",r"/*  part1  */  /*  part2  */"))

print(re.findall(r"(^sunck(.*?)man$)",str))

import re

print("--------------匹配单个字符与数字--------------")
'''
r
.  匹配除换行符以外的任意字符
[0123456789]  []是字符集合,表示匹配方括号中所包含的任意一个字符
[sunck]       匹配's','u','n','c','k'中任意一个字符
[a-z]         匹配任意小写字母
[A-Z]         匹配任意大写字母
[0-9]         匹配任意数字,类似[0123456789]
[0-9a-zA-Z]   匹配任意的数字和字母(注意之间没有空格)
[0-9a-zA-Z_]  匹配任意的数字、字母、下划线(注意之间没有空格)
[^sunck]      匹配除了sunck这几个字母以外的所有字符
^称为脱字符,表示不匹配集合中的字符
[^0-9]        匹配所有的非数字字符
\d            匹配数字,效果[0-9]
\D            匹配非数字字符,效果同[^0-9]
\w            匹配数字,字母和下划线,效果同[0-9a-zA-Z_]
\W            匹配非数字,字母和下划线,效果同[^0-9a-zA-Z_]
\s            匹配任意的空白符(格,换行,回车,换页,制表),效果同
              [ \f\n\r\t]
\S            匹配任意的非空白符,效果同[^ \f\n\r\t]
'''

print(re.search(".","sunck is a good man "))
print(re.search("[0123456789]","sunck is a good man 3"))
print(re.search("[sunck]","sunck is a good man 3"))
print(re.findall("[\d]","sunck is a good man 3"))
print(re.search("\D","sunck is a good man 3"))
print(re.search("\w","_sunck is a good man 3"))
print(re.findall("\d","_sunck is 6a go80d man 3" ))


print("-------------------锚字符(边界字符)-------------------")
'''
^        行首匹配,和[]里的^不是一个意思
$        行尾匹配  

\A       匹配字符串开始,它和^的区别是,\A只匹配整个字符串的开头,即使
         在re.M模式下也不会匹配他行的行首
\Z       匹配字符串的结束,它和$的区别是,\Z只匹配整个字符串的结束,即使
         在re.M模式下也不会匹配他行的行尾
         
\b       匹配一个单词的边界,也就是指单词和空格间的位置
         'er\b'可以匹配never,不能匹配nerve
\B       匹配非单词边界
'''

print(re.search("^sunck","sunck si a good man"))
print(re.search("sunck$","sunck si a good man"))
print(re.search("man$","sunck si a good man"))
print(re.search("^man$","sunck si a good man"))

print(re.search("^sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("^sunck","sunck si a good man\nsunck is a nice man",re.M))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man",re.M))

print(re.search(r"er\b","never"))
print(re.search(r"er\b","nerve"))
print(re.search(r"er\B","never"))
print(re.search(r"er\B","nerve"))





print("-------------------------匹配多个字符-------------------------")

'''
说明:下方的x,y,z,n均为假设的普通字符,不是正则表达式的元字符(xyz)   
      匹配小括号内的xyz(作为一个整体去匹配)
x?    匹配0个或者任意1个x
x*    匹配0个或者任意多个x(.*表示匹配0个或者任意多个字符(换行符除外))
x+    匹配至少一个x
x{n}  匹配确定的n个x(n是一个非负整数)
x{n,} 匹配至少n个x
x{n,m}匹配至少n个最多m个。注意:n <= m
x|y   |表示或,匹配的是x或y
'''
print(re.findall(r"(sunck)","sunck is a good man ,sunck is a nice man "))
print(re.findall(r"0?","sunck is a good man ,sunck is a nice man "))

print(re.findall(r"a?","aaa"))   # 非贪婪匹配(尽可能少的匹配)
print(re.findall(r"a*","aaabaa")) # 贪婪匹配(尽可能多的匹配)
print(re.findall(r".*","aaabaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaabaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3}","aa"))
print(re.findall(r"a{3}","aaaa"))
print(re.findall(r"a{3}","aaaaa"))
print(re.findall(r"a{3}","aaabaa"))

print(re.findall(r"a{3,}","aaaaa"))
print(re.findall(r"a{3,}","aaa"))
print(re.findall(r"a{3,}","aa"))
print(re.findall(r"a{3,}","aaaaabaaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3,6}","aaaaabaaa"))

print(re.findall(r"((s|S)unck)","sunck--Sunck"))
print(re.findall(r"((s|S)unck)","sunck--SuNck"))

# 需求,提取sunck……man,
str = "sunck is a good man!sunck is a nice man!sunck is a very handsome man "
print(re.findall(r"^sunck.*man",str))
print(re.findall(r"^sunck.*man$",str))

print("-------------------特殊-------------------------")
'''
*?  +?  x?   最小匹配   通常都是尽快可能多的匹配,可以用这种方式解决贪婪匹配
(?:x)        类似(xyz),但不表示一个组
'''
# 注释:  /* part1 */  /*  part2  /*
print(re.findall(r"//*.*/*/",r"/*  part1  */  /*  part2  */"))

print(re.findall(r"(^sunck(.*?)man$)",str))


import re

print("--------------匹配单个字符与数字--------------")
'''
r
.  匹配除换行符以外的任意字符
[0123456789]  []是字符集合,表示匹配方括号中所包含的任意一个字符
[sunck]       匹配's','u','n','c','k'中任意一个字符
[a-z]         匹配任意小写字母
[A-Z]         匹配任意大写字母
[0-9]         匹配任意数字,类似[0123456789]
[0-9a-zA-Z]   匹配任意的数字和字母(注意之间没有空格)
[0-9a-zA-Z_]  匹配任意的数字、字母、下划线(注意之间没有空格)
[^sunck]      匹配除了sunck这几个字母以外的所有字符
^称为脱字符,表示不匹配集合中的字符
[^0-9]        匹配所有的非数字字符
\d            匹配数字,效果[0-9]
\D            匹配非数字字符,效果同[^0-9]
\w            匹配数字,字母和下划线,效果同[0-9a-zA-Z_]
\W            匹配非数字,字母和下划线,效果同[^0-9a-zA-Z_]
\s            匹配任意的空白符(格,换行,回车,换页,制表),效果同
              [ \f\n\r\t]
\S            匹配任意的非空白符,效果同[^ \f\n\r\t]
'''

print(re.search(".","sunck is a good man "))
print(re.search("[0123456789]","sunck is a good man 3"))
print(re.search("[sunck]","sunck is a good man 3"))
print(re.findall("[\d]","sunck is a good man 3"))
print(re.search("\D","sunck is a good man 3"))
print(re.search("\w","_sunck is a good man 3"))
print(re.findall("\d","_sunck is 6a go80d man 3" ))


print("-------------------锚字符(边界字符)-------------------")
'''
^        行首匹配,和[]里的^不是一个意思
$        行尾匹配  

\A       匹配字符串开始,它和^的区别是,\A只匹配整个字符串的开头,即使
         在re.M模式下也不会匹配他行的行首
\Z       匹配字符串的结束,它和$的区别是,\Z只匹配整个字符串的结束,即使
         在re.M模式下也不会匹配他行的行尾
         
\b       匹配一个单词的边界,也就是指单词和空格间的位置
         'er\b'可以匹配never,不能匹配nerve
\B       匹配非单词边界
'''

print(re.search("^sunck","sunck si a good man"))
print(re.search("sunck$","sunck si a good man"))
print(re.search("man$","sunck si a good man"))
print(re.search("^man$","sunck si a good man"))

print(re.search("^sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man"))
print(re.search("^sunck","sunck si a good man\nsunck is a nice man",re.M))
print(re.search("A\sunck","sunck si a good man\nsunck is a nice man",re.M))

print(re.search(r"er\b","never"))
print(re.search(r"er\b","nerve"))
print(re.search(r"er\B","never"))
print(re.search(r"er\B","nerve"))





print("-------------------------匹配多个字符-------------------------")

'''
说明:下方的x,y,z,n均为假设的普通字符,不是正则表达式的元字符(xyz)   
      匹配小括号内的xyz(作为一个整体去匹配)
x?    匹配0个或者任意1个x
x*    匹配0个或者任意多个x(.*表示匹配0个或者任意多个字符(换行符除外))
x+    匹配至少一个x
x{n}  匹配确定的n个x(n是一个非负整数)
x{n,} 匹配至少n个x
x{n,m}匹配至少n个最多m个。注意:n <= m
x|y   |表示或,匹配的是x或y
'''
print(re.findall(r"(sunck)","sunck is a good man ,sunck is a nice man "))
print(re.findall(r"0?","sunck is a good man ,sunck is a nice man "))

print(re.findall(r"a?","aaa"))   # 非贪婪匹配(尽可能少的匹配)
print(re.findall(r"a*","aaabaa")) # 贪婪匹配(尽可能多的匹配)
print(re.findall(r".*","aaabaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaa"))# 贪婪匹配(尽可能多的匹配)
print(re.findall(r"a+","aaabaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3}","aa"))
print(re.findall(r"a{3}","aaaa"))
print(re.findall(r"a{3}","aaaaa"))
print(re.findall(r"a{3}","aaabaa"))

print(re.findall(r"a{3,}","aaaaa"))
print(re.findall(r"a{3,}","aaa"))
print(re.findall(r"a{3,}","aa"))
print(re.findall(r"a{3,}","aaaaabaaa"))# 贪婪匹配(尽可能多的匹配)

print(re.findall(r"a{3,6}","aaaaabaaa"))

print(re.findall(r"((s|S)unck)","sunck--Sunck"))
print(re.findall(r"((s|S)unck)","sunck--SuNck"))

# 需求,提取sunck……man,
str = "sunck is a good man!sunck is a nice man!sunck is a very handsome man "
print(re.findall(r"^sunck.*man",str))
print(re.findall(r"^sunck.*man$",str))

print("-------------------特殊-------------------------")
'''
*?  +?  x?   最小匹配   通常都是尽快可能多的匹配,可以用这种方式解决贪婪匹配
(?:x)        类似(xyz),但不表示一个组
'''
# 注释:  /* part1 */  /*  part2  /*
print(re.findall(r"//*.*/*/",r"/*  part1  */  /*  part2  */"))

print(re.findall(r"(^sunck(.*?)man$)",str))

# 测试如下:

--------------匹配单个字符与数字--------------

  PycharmProjects/untitled/正则表达式的元字符.py", line 119, in <module>
<_sre.SRE_Match object; span=(0, 1), match='s'>
    print(re.findall(r"(^sunck(.*?)man$)",str))
<_sre.SRE_Match object; span=(20, 21), match='3'>
  File "E:\lib\re.py", line 222, in findall
<_sre.SRE_Match object; span=(0, 1), match='s'>
    return _compile(pattern, flags).findall(string)
['3']
  File "E:\lib\re.py", line 301, in _compile
<_sre.SRE_Match object; span=(0, 1), match='s'>
    p = sre_compile.compile(pattern, flags)
<_sre.SRE_Match object; span=(0, 1), match='_'>
  File "E:\lib\sre_compile.py", line 562, in compile
['6', '8', '0', '3']
    p = sre_parse.parse(p, flags)
-------------------锚字符(边界字符)-------------------
  File "E:\lib\sre_parse.py", line 869, in parse
<_sre.SRE_Match object; span=(0, 5), match='sunck'>
    raise source.error("unbalanced parenthesis")
None
sre_constants.error: unbalanced parenthesis at position 16
<_sre.SRE_Match object; span=(16, 19), match='man'>
None
<_sre.SRE_Match object; span=(0, 5), match='sunck'>
None
<_sre.SRE_Match object; span=(0, 5), match='sunck'>
None
<_sre.SRE_Match object; span=(3, 5), match='er'>
None
None
<_sre.SRE_Match object; span=(1, 3), match='er'>
-------------------------匹配多个字符-------------------------
['sunck', 'sunck']
['', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '']
['a', 'a', 'a', '']
['aaa', '', 'aa', '']
['aaabaa', '']
['aaa']
['aaa', 'aa']
[]
['aaa']
['aaa']
['aaa']
['aaaaa']
['aaa']
[]
['aaaaa', 'aaa']
['aaaaa', 'aaa']
[('sunck', 's'), ('Sunck', 'S')]
[('sunck', 's')]
['sunck is a good man!sunck is a nice man!sunck is a very handsome man']
[]
-------------------特殊-------------------------
['/*  part1  */  /*  part2  */']


随笔:别拿自己的无知当个性!

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转载自blog.csdn.net/huaxiawudi/article/details/81487018