• Python正则表达式使用经典实例
  • 2017年12月24日
  • 网络收集

下面列出Python正则表达式的几种匹配用法,具体内容如下所示:

此外,关于正则的一切 http://deerchao.net/tutorials/regex/regex.htm

1.测试正则表达式是否匹配字符串的全部或部分

regex=ur"" #正则表达式
if re.search(regex, subject):
do_something()
else:
do_anotherthing()
                  

2.测试正则表达式是否匹配整个字符串

regex=ur"\Z" #正则表达式末尾以\Z结束
if re.match(regex, subject):
    do_something()
else:
    do_anotherthing()
                  

3.创建一个匹配对象 ,然后通过该对象获得匹配细节(Create an object with details about how the regex matches (part of) a string)

regex=ur"" #正则表达式
match = re.search(regex, subject)
if match:
    # match start: match.start()
    # match end (exclusive): atch.end()
    # matched text: match.group()
    do_something()
else:
    do_anotherthing()
                  

4.获取正则表达式所匹配的子串(Get the part of a string matched by the regex)

regex=ur"" #正则表达式
match = re.search(regex, subject)
if match:
    result = match.group()
else:
    result = ""
                  

5. 获取捕获组所匹配的子串 (Get the part of a string matched by a capturing group)

regex=ur"" #正则表达式
match = re.search(regex, subject)
if match:
    result = match.group(1)
else:
    result = ""
                  

6. 获取有名组所匹配的子串 (Get the part of a string matched by a named group)

regex=ur"" #正则表达式
match = re.search(regex, subject)
if match:
result = match.group"groupname")
else:
result = ""
                  

7. 将字符串中所有匹配的子串放入数组中 (Get an array of all regex matches in a string)

result = re.findall(regex, subject)
                  

8.遍历所有匹配的子串 (Iterate over all matches in a string)

for match in re.finditer(r"<(.*?)\s*.*?/\1>", subject)
    # match start: match.start()
    # match end (exclusive): atch.end()
    # matched text: match.group()
                  

9.通过正则表达式字符串创建一个正则表达式对象( Create an object to use the same regex for many operations)

reobj = re.compile(regex)
                  

10.用法1的正则表达式对象版本 (use regex object for if/else branch whether (part of) a string can be matched)

reobj = re.compile(regex)
if reobj.search(subject):
    do_something()
else:
    do_anotherthing()
                  

11.用法2的正则表达式对象版本 (use regex object for if/else branch whether a string can be matched entirely)

reobj = re.compile(r"\Z") #正则表达式末尾以\Z 结束
if reobj.match(subject):
    do_something()
else:
    do_anotherthing()
                  

12.创建一个正则表达式对象,然后通过该对象获得匹配细节 (Create an object with details about how the regex object matches (part of) a string)

reobj = re.compile(regex)
match = reobj.search(subject)
if match:
    # match start: match.start()
    # match end (exclusive): atch.end()
    # matched text: match.group()
    do_something()
else:
    do_anotherthing()
                  

13.用正则表达式对象获取匹配子串( Use regex object to get the part of a string matched by the regex)

reobj = re.compile(regex)
match = reobj.search(subject)
if match:
    result = match.group()
else:
    result = ""
                  

14.用正则表达式对象获取捕获组所匹配的子串 (Use regex object to get the part of a string matched by a capturing group)

reobj = re.compile(regex)
match = reobj.search(subject)
if match:
    result = match.group(1)
else:
    result = ""
                  

15.用正则表达式对象获取有名组所匹配的子串(Use regex object to get the part of a string matched by a named group)

reobj = re.compile(regex)
match = reobj.search(subject)
if match:
    result = match.group("groupname")
else:
    result = ""
                  

16.用正则表达式对象获取所有匹配子串并放入数组 (Use regex object to get an array of all regex matches in a string)

reobj = re.compile(regex)
result = reobj.findall(subject)
                  

17.通过正则表达式对象遍历所有匹配子串 (Use regex object to iterate over all matches in a string)

reobj = re.compile(regex)
for match in reobj.finditer(subject):
    # match start: match.start()
    # match end (exclusive): match.end()
    # matched text: match.group()
                  

字符串替换

1.替换所有匹配的子串

#用newstring替换subject中所有与正则表达式regex匹配的子串
result = re.sub(regex, newstring, subject)
                  

2.替换所有匹配的子串(使用正则表达式对象)

reobj = re.compile(regex)
result = reobj.sub(newstring, subject)
                  

字符串拆分

1.字符串拆分

result = re.split(regex, subject)
                  

2.字符串拆分(使用正则表示式对象)

reobj = re.compile(regex)
result = reobj.split(subject)