I would like to check whether an optional argparse argument has been set by the user or not.
Can I safely check using isset?
Something like this:
if(isset(args.myArg)):
#do something
else:
#do something else
Does this work the same for float / int / string type arguments?
I could set a default parameter and check it (e.g., set myArg = -1, or "" for a string, or "NOT_SET"). However, the value I ultimately want to use is only calculated later in the script. So I would be setting it to -1 as a default, and then updating it to something else later. This seems a little clumsy in comparison with simply checking if the value was set by the user.
I think that optional arguments (specified with --
) are initialized to None
if they are not supplied. So you can test with is not None
. Try the example below:
import argparse as ap
def main():
parser = ap.ArgumentParser(description="My Script")
parser.add_argument("--myArg")
args, leftovers = parser.parse_known_args()
if args.myArg is not None:
print "myArg has been set (value is %s)" % args.myArg