["python","argparse"]
Check if argparse optional argument is set or not

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 def main(): parser = argparse.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