Python正则表达式的用法（1. 匹配）

(作者：玛瑙河，转载请注明作者或出处，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): match.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)

1result = 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): match.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): match.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()