python - Get string between two sub strings with limitation -

i need finding substring using regex, starting example:

given following string:

test_str = "start: 1111 kill 22:22 start: 3333 end" 

i extract string between start , end doesn't involve kill:

wanted_result = (start: 3333 end) 

note: need matches of start blablab end don't have kill between them

several tries failed, latest one:

pattern = re.compile(r'start:(.+?)(([^kill])end)',flags = re.dotall) results = pattern.findall(test_str) 

which results in different result:

result = (' 1111 kill 22:22 start: 3333', ' end', ' end') 

you need use negative lookahead based regex.

pattern = re.compile(r'start:(?:(?!kill).)*?end',flags = re.dotall) 

(?:(?!kill).)*? checking before match character. checks character going matched must not start of substring kill.

example:

>>> import re >>> test_str = "start: 1111 kill 22:22 start: 3333 end" >>> pattern = re.compile(r'start:(?:(?!kill).)*?end',flags = re.dotall) >>> pattern.findall(test_str) ['start: 3333 end']