Pass a list as argument with argparse

Question

Is it possible to pass a list variable as an argument to the argparse module?

It has been seen to use nargs option

parser.add_argument('--my_arg', --nargs='+', type=int)

and pass some values as:

python script.py --my_arg 2 6 9

Instead, is it possible to do the following?

my_list=[2,6,9]

python script.py --my_arg my_list

Answer 1

This depends on the operating system and shell used. For example, if you are on a unix-like system and using zsh, you could do

my_list=(2 6 9)
python script.py --my_arg $my_list

Zsh is quite forgiving here as it will expand entire arrays if you omit the index and, unlike most shells, it won't split elements of my_list into separate words if there are spaces in them. In Bash, I think you have to do something like this

my_list=(1 2 "hello there")
python script.py --my_arg "${my_list[@]}"

Chech the bash manual on arrays for details.