Question

For example: I have a string “abcde2011-09-30.log”, I want to check if this string matchs “(\d){4}-(\d){2}-(\d){2}” ( dont think it has correct syntax, but you get the idea). And I need to split the string into 3 parts: (abcde),(e2011-09-30), (.log). How can I do it in python? Thanks.

Answer 1

There’s a split method in the re module that should work for you.

>>> s = 'abcde2011-09-30.log'
>>> re.split('(\d{4}-\d{2}-\d{2})', s)
('abcde', '2011-09-30', '.log')

If you don’t actually want the date as part of the returned list, just omit the parentheses around the regular expression so that it doesn’t have a capturing group:

>>> re.split('\d{4}-\d{2}-\d{2}', s)
('abcde', '.log')

Be advised that if the pattern matches more than once, i.e. if there is more than one date in the filename, then this will split on both of them. For example,

>>> s2 = 'abcde2011-09-30fghij2012-09-31.log'
>>> re.split('(\d{4}-\d{2}-\d{2})', s2)
('abcde', '2011-09-30', 'fghij', '2012-09-31', '.log')

If this is a problem, you can use the maxsplit argument to split to only split it once, on the first occurrence of the date:

>>> re.split('(\d{4}-\d{2}-\d{2})', s, 1)
('abcde', '2011-09-30', 'fghij2012-09-31.log')