Argparse and "in" option

I have what I think is a trivial issue, but was not able to find the reply.

I have a very simple argparse script:

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('--in', help='Input folder', default='../../in')
parser.add_argument('--out', help='Output folder', default='../../out')
args = parser.parse_args()
print(f'From {args.in} to {args.out}')

This results in an error:

  File "[...]\__main__.py", line 16
    (args.in)
          ^^
SyntaxError: f-string: invalid syntax

The issue, however, is only with the in parameter; if I remove it from the f-string the out parameter is printed successfully.

If I try to print the args variable I get

Namespace(in='../../in', out='../../out')

which means that the in parameter is read. I assume the .in way is reserved, but then… how do I access it?

If it is useful, I’m using Python 3.10.4 on Windows

>Solution :

You cannot – Why can’t attribute names be Python keywords?

But, at the parsing level, you can specify dest argument, which will change the name that is assigned to the command line argument in Python.

parser.add_argument('--in', dest = "_in", help='Input folder', default='../../in')

print(f'From {args._in} to {args.out}')

This way you can still start the program with --in ... --out ... arguments without breaking the code.