我如何找到两个子字符串('123STRINGabc' -> '字符串')之间的字符串?

我现在的方法是这样的:

>>> start = 'asdf=5;'
>>> end = '123jasd'
>>> s = 'asdf=5;iwantthis123jasd'
>>> print((s.split(start))[1].split(end)[0])
iwantthis

然而,这似乎非常低效且不符合python规则。有什么更好的方法来做这样的事情吗?

忘了说: 字符串可能不是以start和end开始和结束的。他们可能会有更多的字符之前和之后。


当前回答

这本质上是cji的答案——7月30日10日5:58。 我更改了try except结构,以便更清楚地说明导致异常的原因。

def find_between( inputStr, firstSubstr, lastSubstr ):
'''
find between firstSubstr and lastSubstr in inputStr  STARTING FROM THE LEFT
    http://stackoverflow.com/questions/3368969/find-string-between-two-substrings
        above also has a func that does this FROM THE RIGHT   
'''
start, end = (-1,-1)
try:
    start = inputStr.index( firstSubstr ) + len( firstSubstr )
except ValueError:
    print '    ValueError: ',
    print "firstSubstr=%s  -  "%( firstSubstr ), 
    print sys.exc_info()[1]

try:
    end = inputStr.index( lastSubstr, start )       
except ValueError:
    print '    ValueError: ',
    print "lastSubstr=%s  -  "%( lastSubstr ), 
    print sys.exc_info()[1]

return inputStr[start:end]    

其他回答

这本质上是cji的答案——7月30日10日5:58。 我更改了try except结构,以便更清楚地说明导致异常的原因。

def find_between( inputStr, firstSubstr, lastSubstr ):
'''
find between firstSubstr and lastSubstr in inputStr  STARTING FROM THE LEFT
    http://stackoverflow.com/questions/3368969/find-string-between-two-substrings
        above also has a func that does this FROM THE RIGHT   
'''
start, end = (-1,-1)
try:
    start = inputStr.index( firstSubstr ) + len( firstSubstr )
except ValueError:
    print '    ValueError: ',
    print "firstSubstr=%s  -  "%( firstSubstr ), 
    print sys.exc_info()[1]

try:
    end = inputStr.index( lastSubstr, start )       
except ValueError:
    print '    ValueError: ',
    print "lastSubstr=%s  -  "%( lastSubstr ), 
    print sys.exc_info()[1]

return inputStr[start:end]    
s[len(start):-len(end)]

这对我来说似乎更直接:

import re

s = 'asdf=5;iwantthis123jasd'
x= re.search('iwantthis',s)
print(s[x.start():x.end()])

我的方法是,

find index of start string in s => i
find index of end string in s => j

substring = substring(i+len(start) to j-1)

要提取STRING,请尝试:

myString = '123STRINGabc'
startString = '123'
endString = 'abc'

mySubString=myString[myString.find(startString)+len(startString):myString.find(endString)]