thorink thorink -4 years ago 61
Python Question

How can use python's argparse with a predefined argument string?

I want to use the pythons argparse module to parse my cli parameter string. This works for the parameters a pass from terminal, but not with a given string.

import argparse

parser = argparse.ArgumentParser(description='Argparse Test script')
parser.add_argument("param", help='some parameter')

argString = 'someTestFile'

args = parser.parse_args(argString)

If I run this script I get this output:

usage: [-h] param error: unrecognized arguments: o m e T e s t F i l e

is somehow transformed in
o m e T e s t F i l e
. As already mentioned, it works if I pass the filename from the terminal.

I could imagine, that this has something to do with string encodings. Does someone has an idea how to fix this?

Answer Source

Ah, no no no. parser.parse_args() expects a sequence in the same form as sys.argv[1:]. If you treat a string like a sys.argv sequence, you get ['s', 'o', 'm', 'e', 'T', 'e', 's', 't', 'F', 'i', 'l', 'e']. 's' becomes the relevant argument, and then the rest of the string is unparseable.

Instead, you probably want to pass in parser.parse_args(['someTestFile'])

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