Match RegEx pattern within pattern

Question

Folks,

I have to match the following pattern:

First letter must be N Second any letter except P Third have to be S or T and the Fourth any letter except P again.

The string is only capital letters, no number, white spaces, etc.

So using python this is what I got so far:

import re
strRegex = r"N[^P][ST][^P]"
objRegex = re.compile(strRegex)

print objRegex.findall('NNSTL')

This will print: NNST

What I expect is: NNST and NSTL

Thanks

`re.findall` will only return _non-overlapping_ matches - that is, starting at any given position, it will find the _first_ way to match, not _all possible_ ways. — Hugh Bothwell, Feb 26 '14 at 02:26
This answer should help you: http://stackoverflow.com/a/11430936/138088 — Daniel F. Thornton, Feb 26 '14 at 02:26
possible duplicate of [How to find overlapping matches with a regexp?](http://stackoverflow.com/questions/11430863/how-to-find-overlapping-matches-with-a-regexp) — Daniel F. Thornton, Feb 26 '14 at 02:27
duplicate of http://stackoverflow.com/questions/22030459/finding-all-possible-substrings-within-a-string-python-regex — Hypothetical Ninja, Feb 26 '14 at 04:46

score 1 · Answer 1 · answered Feb 26 '14 at 05:15

re.findall will only return non-overlapping matches

Try this:

    >>> strRegex = r"N[^P][ST][^P]"
    >>> regex = compile(strRegex)
    >>> def newfind(regex,str,pos=0):
    ...    result=regex.search(str,pos)
    ...    if result is None: return []
    ...    else: return [result.group()]+newfind(regex,str,result.start()+1)
    ...
    >>>
    >>> newfind(regex,'NNSTL')
    ['NNST', 'NSTL']

Reference: https://mail.python.org/pipermail/tutor/2005-September/041126.html

Match RegEx pattern within pattern

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