'Regex - Checks a letter repeating at least twice

I want to check whether a string includes the letter a (lowercase or uppercase) at least twice. I wrote the regex pattern and checked its working on regex101.com.

[aA]+[^aA]*[aA]+

Sample strings to match:

banana   #True
pineapple  #False
Animal Kingdom  #True
A is for apple  #True

Though the code is working as expected, I am concerned about whether there are better ways to get it done, or are there some cases that aren't going to match with my regex.

regex


Solution 1:[1]

pineapple shouldn't match, should it?

I would suggest ([aA].*){2,} because I think it's easier to read.

Here with unit tests based on your suggestions: https://regex101.com/r/WJnTW5/2

Solution 2:[2]

Try this one very simple:

    (r"a.*a", text, re.IGNORECASE)

Another way is:

if you put [Aa]{n} it means you want A/a to be repeated for a consecutively n times which is not in this case as a is separated by characters for example in banana, a is separated by n... so we use [Aa].*[Aa]

    (r"[Aa].*[Aa]", text)

Both ways it works.

Solution 3:[3]

i wrote this and it worked:

re.search(r"a[a-z ]*a", text, re.IGNORECASE)

so find the first a, go through any of these characters plus the " ", any number of times until you find another a, and this regardless of the case.

Solution 4:[4]

This way will work:

(r"a+.+a", text.lower())

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Paul
Solution 2
Solution 3 Gustavo Amaya
Solution 4 Andrew

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