Specify date format for Python argparse input arguments
Per the documentation:
The
type
keyword argument ofadd_argument()
allows any necessary type-checking and type conversions to be performed ... The argument totype
can be any callable that accepts a single string.
You could do something like:
def valid_date(s):
try:
return datetime.strptime(s, "%Y-%m-%d")
except ValueError:
msg = "not a valid date: {0!r}".format(s)
raise argparse.ArgumentTypeError(msg)
Then use that as type
:
parser.add_argument(
"-s",
"--startdate",
help="The Start Date - format YYYY-MM-DD",
required=True,
type=valid_date
)
Just to add on to the answer above, you can use a lambda function if you want to keep it to a one-liner. For example:
parser.add_argument('--date', type=lambda d: datetime.strptime(d, '%Y%m%d'))
Old thread but the question was still relevant for me at least!