How do Python regular expressions do string replacement instances

Python regular expressions are often applied to string replacement code in use. There are many people do not know how to solve this problem, the following code tells you that the problem is extremely simple, I hope you have some results.

1. Replace all matched substrings with newstring to replace all substrings in subject that match the regular expression regex

result, number = re.subn(regex, newstring, subject) 

2. Replace all matched substrings (using regular expression objects)

rereobj = re.compile(regex) 
result, number = reobj.subn(newstring, subject)

Python string split

reresult = re.split(regex, subject) 

String splitting (using regular representation objects)

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

Here is a list of several matching USES of Python regular expressions:

1. Test whether the regular expression matches all or part of the string regex=ur"..." # regular expression

if re.search(regex, subject): 
do_something() 
else:
do_anotherthing()

2. Test whether the regular expression matches the entire string regex=ur"... \Z" # ends with \Z at the end of the regular expression

if re.match(regex, subject): 
do_something() 
else: 
do_anotherthing() 

3. Create a match object and get the match details regex=ur"..." # regular expression

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()