CODEWITHSUNDEEP
pythonregexunique
sotn
sotn

Reputation: 2101

Python regex to match multiple unique values

I need to match a string with specific letters but none of the letters should be duplicated. For example, [AEIOU] should not match 'AAEIOU' or 'AAEEIOU'. It should only match 'AEIOU' and the order of the letters should not matter. I tried using the exact quantifier with {} but did not work.

Upvotes: 1

Views: 1255

Answers (3)

sytech
sytech

Reputation: 41051

Not using regex, but you can use python string methods to count characters in a string. This can be used to develop a filter function that, effectively, can get you the results you want.

def has_all_unique(s):
    """Returns True of the string has exactly 1 of each vowel"""
    return all(s.count(char) == 1 for char in 'AEIOU')

tests = ['AAEIOU', 'AAEEIOU', 'AEIOU']

for match in filter(has_all_unique, tests):
    print(match)

Result would be just the one match meeting the condition, 

AEIOU

This isn't the most performant option, but is simple and readable.

Upvotes: 0

user3483203
user3483203

Reputation: 51165

You can use negative lookahead:

^(?!.*(.).*\1)[AEIOU]+$

Whatever you put in the brackets will be the subset of characters you select from.

>>> import re
>>> tests = ['AAEIOU', 'AAEEIOU', 'AEIOU']
>>> for test in tests:
..    print(re.match(r'^(?!.*(.).*\1)[AEIOU]+$', test))
None
None
<_sre.SRE_Match object; span=(0, 5), match='AEIOU'>

Upvotes: 2

William
William

Reputation: 81

This maybe inefficient, but maybe use counters? Construct a counter for each, then check if they are equal?

Upvotes: 0

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