parse_args do not include None values in Namespace

Question

parser = argparse.ArgumentParser(prog='PROG')
parser.add_argument('-x')
parser.add_argument('--foo')
ns = parser.parse_args(['-x', 'X'])  # Namespace(foo=None, x='X')

Is there any way to have parse_args avoid including None values in the returned Namespace? So that

vars(ns) == {k:v for k,v in vars(ns).items() if v is not None}

without doing it manually.

Answer 1

yes, add argument_default=argparse.SUPPRESS (full doc)

to globally suppress attribute creation on parse_args() calls, we supply argument_default=SUPPRESS:

import argparse

parser = argparse.ArgumentParser(prog='PROG',argument_default=argparse.SUPPRESS)
parser.add_argument('-x')
parser.add_argument('--foo')
ns = parser.parse_args(['-x', 'X'])

now:

>>> ns
Namespace(x='X')