Regex for existence of some words whose order doesn't matter

python, regex, regex-lookarounds, string, string-matching

Solution

See this regex:

/^(?=.*Tim)(?=.*stupid).+/

Regex explanation:

- `^` Asserts position at start of string.

- `(?=.*Tim)` Asserts that "Tim" is present in the string.

- `(?=.*stupid)` Asserts that "stupid" is present in the string.

- `.+`Now that our phrases are present, this string is valid. Go ahead and use `.+` or - `.++` to match the entire string.

To use lookaheads more exclusively, you can add another `(?=.*<to_assert>)` group. The entire regex can be simplified as `/^(?=.*Tim).*stupid/`.

See a regex demo!

>>> import re
>>> str ="""
... Tim is so stupid.
... stupid Tim!
... Tim foobar barfoo.
... Where is Tim?"""
>>> m = re.findall(r'^(?=.*Tim)(?=.*stupid).+$', str, re.MULTILINE)
>>> m
['Tim is so stupid.', 'stupid Tim!']
>>> m = re.findall(r'^(?=.*Tim).*stupid', str, re.MULTILINE)
>>> m
['Tim is so stupid.', 'stupid Tim!']

Read more:

- Regex with exclusion chars and another regex

Problem

I would like to write a regex for searching for the existence of some words, but their order of appearance doesn't matter. For example, search for "Tim" and "stupid". My regex is `Tim.*stupid|stupid.*Tim`. But is it possible to write a simpler regex (e.g. so that the two words appear just once in the regex itself)?

Original source