how to allow -non_number as arguments in python argparse

Question

python test.py --arg -foo -bar
test.py: error: argument --arg: expected at least one argument

python test.py --arg -8
['-8']

How do I allow -non_number to work with argparse?

Is there a way to disable short arguments?

This is the problem of handling an argument that looks like a flag: https://stackoverflow.com/questions/48322986/python-argparse-passing-argument-to-argument; https://stackoverflow.com/questions/16174992/cant-get-argparse-to-read-quoted-string-with-dashes-in-it — hpaulj, Jan 24 '18 at 21:35

wim · Accepted Answer · 2018-01-25T18:28:34.040

3

Call it like this:

python test.py --arg='-foo'

To allow specifying multiple:

parser.add_argument('--arg', action='append')
# call like python test.py --arg=-foo --arg=-bar

edited Jan 25 '18 at 18:28

answered Jan 24 '18 at 21:49

wim

doesn't work for more than 1 arguments though. Edited question to reflect – Hec Jan 25 '18 at 18:23

the_storyteller · Answer 2 · 2018-01-24T21:44:25.257

I think you're looking for the nargs parameter to argparser.

parser.add_argument('--arg', nargs='?')

At the moment, --arg is interpreting the value '-8' as the input, whereas it thinks '-f' (with parameters 'oo') is a new argument.

Alternatively, you could use action='store_true', which will represent the presence or absence of the argument with a boolean.

parser.add_argument('--arg', action='store_true')

2 Answers2