Python regex lookbehind and lookahead

Question

I need to match the string \"foo\" from a string with this format:

string = \"/foo/boo/poo\"

I tied this code:

poo = \"poo\         


        

Answer 1

Hey try the following regex:

(?<=/).*(?=/poo)
^^^^^^

It will not take into account your first slash in the result.

Tested regex101: https://regex101.com/r/yzMkTg/1

Transform your code in the following way and it should work:

poo = "poo"
foo = re.match('(?<=/).*(?=/' + re.escape(poo) + ')', string).group(0)

Have a quick look at this link for more information about the behavior of Positive lookahead and Positive lookbehind

http://www.rexegg.com/regex-quickstart.html

Answer 2

You are missing a < in your lookbehind!

Lookbehinds look like this:

(?<=...)

not like this:

(?=...)

That would be a lookahead!

So,

(?<=/).*(?=/poo)