最全正则表达式使用规则全理解 | 配Python实际全测试例子

本文链接：https://blog.youkuaiyun.com/qq_45258618/article/details/141756688

首先是Python实际全测试例子然后是正则表达式使用规则全理解

首先是Python实际全测试

不同编程语言规则基本相同

正则表达式具有匹配不重叠的特点，已经匹配过的不在匹配

下面的代码可直接复制运行

import re
from re import match

#匹配所有正则表达式方法：（文字，正则表达式）
def to_match(words,pattern,No):
    matches = re.findall(pattern,words)
    if matches:
        for match in matches:
            print("No."+str(No)+": ",match)
    else:
        print("No." + str(No) +": No Match")

"""
（文字，正则表达式，序号）
第一个参数是原字符串，第二个是正则表达式，第三个是序号
"""
"""
成功人chen某
24.9
"""

"""
建议将看过的代码注释
便于查看
"""

    # 1，单个匹配
print("\n\n1，单个匹配")
# 匹配一个字符：.
to_match("nuosu",".....",1)
to_match("abcdefg","..",2)
# No.1:  nuosu
# No.2:  ab
# No.2:  cd
# No.2:  ef

# 匹配一个自己：
to_match("nuosu","u",1)
to_match("abcdefg","cde",2)
# No.1:  u
# No.1:  u
# No.2:  cde

    # 2，位置匹配
print("\n\n2，位置匹配")
# 匹配开头：^
to_match("nuosu","nuo",1)
to_match("nuosu","abc",2)
# No.1:  nuo
# No.2: No Match

# 匹配结尾：$
to_match("nuosu","su",1)
to_match("nuosu","abc",2)
# No.1:  su
# No.2: No Match

    # 3，个数匹配
print("\n\n3，个数匹配")
# 零个或一个：?
to_match("nuosu","nuo?",1)
to_match("nuosu","nuoo?",2)
to_match("nuosu","nuoos?",3)
# No.1:  nuo
# No.2:  nuo
# No.3: No Match

print("\n\n3，个数匹配")
# 大于等于零个：*
to_match("nuosu","nuo*",1)
to_match("nuosu","nuoo*",2)
to_match("nuosu","nuoos*",3)
# No.1:  nuo
# No.2:  nuo
# No.3: No Match

# 大于等于一个：+
to_match("nuosu","nuo+",1)
to_match("nuosu","nuoo+",2)
# No.1:  nuo
# No.2: No Match

    # 4，转义匹配
print("4，转义匹配")
to_match("nuo..su","nuo\\.",1)
to_match("nuo..su","\\.",2)
# No.1:  nuo.
# No.2:  .
# No.2:  .

    # 5，括号操作
print("\n\n5，括号操作")
# { }   个数匹配 限制出现次数    a{2}    限制a出现两次
print("No.A")
to_match("nuosu",r"u",1)
to_match("nuuuuosuu",r"u{2}",2)
# No.1:  u
# No.1:  u
# No.2:  uu
# No.2:  uu
# No.2:  uu

# { ,}：a{m,n}    限制a出现范围为n，m之间
print("No.B")
to_match("nuosu",r"u{2,3}",1)
to_match("nuuuuosuu",r"u{2,3}",2)
# No.1: No Match
# No.2:  uuu
# No.2:  uu

# [ ]   匹配的字符在[]中
print("No.C")
to_match("nuosu",r"[A-Z]uo",1)
to_match("Nuosu",r"[A-Z]uo",2)
# No.1: No Match
# No.2:  Nuo
to_match("nuosu",r"[Nu]",3)
to_match("Nuosu",r"[Nu]",4)
# No.3:  u
# No.3:  u
# No.4:  N
# No.4:  u
# No.4:  u

# [^ ]  排除在[]中出现的字符
print("No.D")
to_match("nuosu","[A-Z]uo",1)
to_match("Nuosu","[A-Z]uo",2)
# No.1: No Match
# No.2:  Nuo

# ( ) 捕获 把()内做作为一组提出来
print("No.E")
to_match("nuosu","(nuo)",1)
to_match("nuosu","(nuo)su",2)
# No.1:  nuo
# No.2:  nuo

# ( | ) 捕获 把以|分隔的作为一组提取出来
print("No.F")
to_match("nuosu","(nuo|uos)",1)
to_match("nuosu","(nu|os|u)",2)
# No.1:  nuo
# No.2:  nu
# No.2:  os
# No.2:  u

# (?: ) (?:abc)   捕获 把在相应的位置有abc的地方提取出来
print("No.G")
to_match("nuosu","(?:uo)",1)
to_match("nuosu","(?:uo)su",2)
to_match("nuosu","n(?:uo)",3)
to_match("nuosu","n(?:uo)su",4)
# No.1:  uo
# No.2:  uosu
# No.3:  nuo
# No.4:  nuosu

# (?= ) xx(?=abc) 非捕获 把后面紧跟abc的xx提取出来不包括abc
print("No.H")
to_match("nuosu","(?=os)",1)#相当于""空
to_match("nuosu","nu(?=os)",2)
# No.1:
# No.2:  nu

# (?! ) xx(?!abc)   非捕获 把后面不紧跟abc的xx提取出来不包括abc
print("No.I")
to_match("nuosu","(?!abc)",1)#相当于""空
to_match("nuosu",".(?!abc)",2)
to_match("nuosu","nu(?!abc)",3)
to_match("nuosu","nu(?!osu)",4)
# No.1:
# No.1:
# No.1:
# No.1:
# No.1:
# No.1:
# No.2:  n
# No.2:  u
# No.2:  o
# No.2:  s
# No.2:  u
# No.3:  nu
# No.4: No Match

# (?<= ) (?<=abc)   非捕获 把前面紧跟abc的xx提取出来不包括abc
print("No.J")
to_match("nuosu","(?<=nu)",1)#相当于""空
to_match("nuosu","(?<=nu).",2)
to_match("nuosu","(?<=nu)osu",3)
# No.1:  
# No.2:  o
# No.3:  osu

# (?<! )(?<!abc)xx   非捕获 把前面不紧跟abc的xx提取出来不包括abc
print("No.K")
to_match("nuosu","(?<!nu)",1)#相当于""空
to_match("nuosu","(?<!nu).",2)
to_match("nuosu","(?<!nu)osu",3)
# No.1:
# No.1:
# No.1:
# No.1:
# No.1:
# No.2:  n
# No.2:  u
# No.2:  s
# No.2:  u
# No.3: No Match

# (?=() | ) 条件匹配    (?=(abc)de|fg) 如果成功匹配abc，则匹配de，否则匹配fg
print("No.L")
to_match("nuosu","(?=(nuo)su|abc)",1)
to_match("nuosu","(?=(o)su|u)",2)
# No.1:  nuo
# No.2:  
# No.2:  o
# No.2:  

    # 6，其他
print("\n\n6，其他")
# \d\w
to_match("nuosu","\\d",1)
to_match("nuosu","\\w\\w\\w",2)
# No.1: No Match
# No.2:  nuo

# | 选择
to_match("nuosu","su|us",1)
to_match("nuous","su|us",2)
# No.1:  su
# No.2:  us

    # 7,嵌套组合
print("\n\n7,嵌套组合")
to_match("nuonuouououonaoaonsu","(n)((uo)+|(ao)+)",1)
# No.1:  ('n', 'uo', 'uo', '')
# No.1:  ('n', 'uouououo', 'uo', '')
# No.1:  ('n', 'aoao', '', 'ao')


    # 8,命名捕获组
import re
print("\n\n8,命名捕获组")
# 参数：(正则表达式，字符串)
match = re.search(r"(osu)--(AY)","nuosu--AYI")
if match:
    No1,No2 = match.groups()
    print(f"No1 is {No1},No2 is {No2}")
    # No1 is osu,No2 is AY
else:
    print("No Match")


    # 9,贪心
    single_to_match("nuoooosuoosu","(.+?)su",1)
    single_to_match("nuoooosuoosu","(.+)su",2)#贪心
# No.1:  nuoooo
# No.2:  nuoooosuoo



#匹配第一个正则表达式方法：（文字，正则表达式）
def single_to_match(words,pattern,No):
    match = re.search(pattern,words)
    if match:
        print("No." + str(No) + ": ", match.group(1))
    else:
        print("No." + str(No) +": No Match")