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常見的python正則用法實例講解

 更新時間:2016年06月21日 09:21:30   作者:2778085001  
這篇文章為大家詳細主要介紹了常見的python正則用法實例,列舉Python正則表達式的幾種匹配用法,感興趣的小伙伴們可以參考一下

下面列出Python正則表達式的幾種匹配用法:
此外,關(guān)于正則的一切http://deerchao.net/tutorials/regex/regex.htm 

1.測試正則表達式是否匹配字符串的全部或部分 

regex=ur"" #正則表達式
if re.search(regex, subject):
 do_something()
else:
 do_anotherthing()

2.測試正則表達式是否匹配整個字符串 

regex=ur"\Z" #正則表達式末尾以\Z結(jié)束
if re.match(regex, subject):
     do_something()
else:
     do_anotherthing()

3.創(chuàng)建一個匹配對象,然后通過該對象獲得匹配細節(jié)(Create an object with details about how the regex matches (part of) a string) 

regex=ur"" #正則表達式
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.獲取正則表達式所匹配的子串(Get the part of a string matched by the regex) 

regex=ur"" #正則表達式
match = re.search(regex, subject)
if match:
     result = match.group()
else:
     result = ""

5. 獲取捕獲組所匹配的子串(Get the part of a string matched by a capturing group) 

regex=ur"" #正則表達式
match = re.search(regex, subject)
if match:
     result = match.group(1)
else:
     result = ""

6. 獲取有名組所匹配的子串(Get the part of a string matched by a named group) 

regex=ur"" #正則表達式
match = re.search(regex, subject)
 if match:
 result = match.group"groupname")
 else:
 result = ""

7. 將字符串中所有匹配的子串放入數(shù)組中(Get an array of all regex matches in a string) 

result = re.findall(regex, subject)

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

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

9.通過正則表達式字符串創(chuàng)建一個正則表達式對象(Create an object to use the same regex for many operations) 

reobj = re.compile(regex)

10.用法1的正則表達式對象版本(use regex object for if/else branch whether (part of) a string can be matched) 

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

11.用法2的正則表達式對象版本(use regex object for if/else branch whether a string can be matched entirely) 

reobj = re.compile(r"\Z") #正則表達式末尾以\Z 結(jié)束
if reobj.match(subject):
 &nbsp;&nbsp;&nbsp;&nbsp;do_something()
else:
 &nbsp;&nbsp;&nbsp;&nbsp;do_anotherthing()

 12.創(chuàng)建一個正則表達式對象,然后通過該對象獲得匹配細節(jié)(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:
 &nbsp;&nbsp;&nbsp;&nbsp;# match start: match.start()
 &nbsp;&nbsp;&nbsp;&nbsp;# match end (exclusive): atch.end()
 &nbsp;&nbsp;&nbsp;&nbsp;# matched text: match.group()
 &nbsp;&nbsp;&nbsp;&nbsp;do_something()
else:
 &nbsp;&nbsp;&nbsp;&nbsp;do_anotherthing()

13.用正則表達式對象獲取匹配子串(Use regex object to get the part of a string matched by the regex) 

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

14.用正則表達式對象獲取捕獲組所匹配的子串(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:
 &nbsp;&nbsp;&nbsp;&nbsp;result = match.group(1)
else:
 &nbsp;&nbsp;&nbsp;&nbsp;result = ""

15.用正則表達式對象獲取有名組所匹配的子串(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:
 &nbsp;&nbsp;&nbsp;&nbsp;result = match.group("groupname")
else:
 &nbsp;&nbsp;&nbsp;&nbsp;result = ""

16.用正則表達式對象獲取所有匹配子串并放入數(shù)組(Use regex object to get an array of all regex matches in a string) 

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

17.通過正則表達式對象遍歷所有匹配子串(Use regex object to iterate over all matches in a string) 

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


18.字符串替換
 1).替換所有匹配的子串 

#用newstring替換subject中所有與正則表達式regex匹配的子串
result = re.sub(regex, newstring, subject)

2).替換所有匹配的子串(使用正則表達式對象) 

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

19.字符串拆分
 1).字符串拆分 

result = re.split(regex, subject)

2).字符串拆分(使用正則表示式對象)
reobj = re.compile(regex)
 result = reobj.split(subject)

以上就是本文的全部內(nèi)容,希望對大家的學習有所幫助,也希望大家多多支持腳本之家。

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