Frozenset Intersection with Wildcards

Question

I'm trying to intersect frozensets in Python, but not getting the desired result. My intersection array, LCC, has 100s of strings.

LCC = ['A','E...']
fs1 = frozenset('A')
fs2 = frozenset('E830')
fs1.intersection(LCC)
fs2.intersection(LCC)

The results are:

frozenset({'A'})
frozenset()

I would expect the second function to yield frozenset({'E830'})

Does anyone known how to get this to work with wildcards? Or is it impossible since the string being passed in to LCC is interpreting the wildcards literally?

Answer 1

I assume your '...' is a wildcard pattern meaning any characters of length three.(Regular expression syntax)

You can use regular expressions like this.

import re

LCC = ['A', 'E...']
fs = frozenset({'A', 'E830', 'E2'})

re_patterns = [re.compile(pattern) for pattern in LCC]
intersection = {e for e in fs for pattern in re_patterns
    if re.fullmatch(pattern, e)}
print(intersection)

This will output the following.

{'A', 'E830'}