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[Neil]

Jach Feng <jfong at ms4.hinet.net> wrote:
> I want to distinguish between numbers with/without a dot attached:
> 
>>>> text = 'ch 1. is\nch 23. is\nch 4 is\nch 56 is\n'
>>>> re.compile(r'ch \d{1,}[.]').findall(text)
> ['ch 1.', 'ch 23.']
>>>> re.compile(r'ch \d{1,}[^.]').findall(text)
> ['ch 23', 'ch 4 ', 'ch 56 ']
> 
> I can guess why the 'ch 23' appears in the second list. But how to get rid of it?
> 
> --Jach

Does

>>> re.findall(r'ch\s+\d+(?![.\d])',text)

do what you want?  This matches "ch", then any nonzero number of
whitespaces, then any nonzero number of digits, provided this is not
followed by a dot or another digit.