Python正则表达式的用法（1. 匹配）

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　　(作者：玛瑙河，转载请注明作者或出处， )　
　　
　　下面列出Python正则表达式的几种匹配用法：
　　1.测试正则表达式是否匹配字符串的全部或部分


1 regex=ur" " #正则表达式
2if re.search(regex, subject):
3    do_something()
4else:
5    do_anotherthing()
6　　2.测试正则表达式是否匹配整个字符串


1regex=ur"\Z" #正则表达式末尾以\Z结束
2if re.match(regex, subject):
3    do_something()
4else:
5    do_anotherthing()
6　　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)


1regex=ur"" #正则表达式
2match = re.search(regex, subject)
3if match:
4    # match start: match.start()
5    # match end (exclusive): match.end()
6    # matched text: match.group()
7    do_something()
8else:
9    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)


1regex=ur"" #正则表达式
2match = re.search(regex, subject)
3if match:
4    result = match.group()
5else:
6    result = ""　　5. 获取捕获组所匹配的子串(Get the part of a string matched by a capturing group)


1regex=ur"" #正则表达式
2match = re.search(regex, subject)
3if match:
4    result = match.group(1)
5else:
6    result = ""　　6. 获取有名组所匹配的子串(Get the part of a string matched by a named group)


1regex=ur"" #正则表达式
2match = re.search(regex, subject)
3if match:
4    result = match.group("groupname")
5else:
6    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)


1result = re.findall(regex, subject)　　8.遍历所有匹配的子串(Iterate over all matches in a string)


1for match in re.finditer(r"", subject)
2    # match start: match.start()
3    # match end (exclusive): match.end()
4    # 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)


1reobj = 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）


1reobj = re.compile(regex)
2if reobj.search(subject):
3    do_something()
4else:
5    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）


1reobj = re.compile(r"\Z")　＃正则表达式末尾以\Z 结束
2if reobj.match(subject):
3    do_something()
4else:
5    do_anotherthing()
6　　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）


1reobj = re.compile(regex)
2match = reobj.search(subject)
3if match:
4    # match start: match.start()
5    # match end (exclusive): match.end()
6    # matched text: match.group()
7    do_something()
8else:
9    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）


1reobj = re.compile(regex)
2match = reobj.search(subject)
3if match:
4    result = match.group()
5else:
6    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）


1reobj = re.compile(regex)
2match = reobj.search(subject)
3if match:
4    result = match.group(1)
5else:
6    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）


1reobj = re.compile(regex)
2match = reobj.search(subject)
3if match:
4    result = match.group("groupname")
5else:
6    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）


1reobj = re.compile(regex)
2result = 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）


1reobj = re.compile(regex)
2for match in reobj.finditer(subject):
3    # match start: match.start()
4    # match end (exclusive): match.end()
5    # matched text: match.group()