Python正则表达式的几种匹配用法

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

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)