python - Regex statement to check for 3 capital letters? -

i need regex statement check 3 capital letters in row.

for example should match: abc, aabc, abcabc

but should not match: aabbbc, abcde

at moment statement:

'[^a-z]*[a-z]{3}[^a-z]*' 

but matches abcde, doing wrong?

thanks in advance.

regex

(?<![a-z])[a-z]{3}(?![a-z]) 

explanation

i specified negative lookbehind , negative lookahead before , after middle regex 3 capitals in row, respectively.

this better option compared using negated character class because match when there no characters left or right of string.

online demonstration

demo

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as python code, haven't figured out how print out actual matches,
syntax:

using re.match:

>>> import re >>> p = re.compile(r'(?<![a-z])[a-z]{3}(?![a-z])') >>> s = '''abc ... aabc ... abcabcabcabcdabcabcdedededa ... abcde''' >>> result = p.match(s) >>> result.group() 'abc' 

using re.search:

>>> import re >>> p = re.compile(r'(?<![a-z])[a-z]{3}(?![a-z])') >>> s = 'abcabcde' >>> p.search(s).group() 'abc'