Convert HH:MM:SS timestamps in a list to seconds only

timetosec.py

#!/usr/bin/python3 -ttu
#
# For a list in format hh:mm:ss - hh:mm:ss, where hh: and mm: are optional, return seconds instead
#
# Free to use or critique, its not complex enough for licensing

import re
import sys

# Re-formatted for better visual parsing
timestampre = re.compile(
    r"("
     r"((?P<shr>[0-9]+):)?"
     r"((?P<smin>[0-9]+):)"
    r")?"
    r"(?P<ssec>[0-9]+)"
    r"\s*-\s*"
    r"("
     r"((?P<ehr>[0-9]+):)?"
     r"((?P<emin>[0-9]+):)"
    r")?"
    r"(?P<esec>[0-9]+)"
    )

def zeroifnone(val):
    return 0 if val is None else int(val)

def secfromlist(h,m,s):
    return 3600 * zeroifnone(h) + 60 * zeroifnone(m) + zeroifnone(s)

def timetosec(sourcefile):
    with open(sourcefile, "r") as source:
        for line in source:
            data = timestampre.match(line).groupdict()
            stime = secfromlist(data['shr'], data['smin'], data['ssec'])
            etime = secfromlist(data['ehr'], data['emin'], data['esec'])
            yield (stime, etime)
            
if __name__ == "__main__":
    for (start,end) in timetosec(sys.argv[1]):
        print("%d - %d" % (start,end))