RegEx Python

Regular Expressions in Python syntax

Parse a simple date

This format is used by the `motion` command. This parses the date from filenames in this example format:

   02-20070505085051-04.jpg

The return format is a sequence the same as used in the standard Python library time module. This is pretty trivial, but shows using named sub-expressions.

def date_from_filename (filename):
    m = re.match(".*?[0-9]{2}-(?P<YEAR>[0-9]{4})(?P<MONTH>[0-9]{2})(?P<DAY>[0-9]{2})(?P<HOUR>[0-9]{2})(?P<MIN>[0-9]{2})(?P<SEC>[0-9]{2})-(?P<SEQ>[0-9]{2}).*?", filename)
    if m is None:
        print "Bad date parse in filename:", filename
        return None
    day   = int(m.group('DAY'))
    month = int(m.group('MONTH'))
    year  = int(m.group('YEAR'))
    hour  = int(m.group('HOUR'))
    min   = int(m.group('MIN'))
    sec   = int(m.group('SEC'))
    dts = (year, month, day, hour, min, sec, 0, 1, -1)
    return dts