CODEWITHSUNDEEP
python-2.7argparse
Russell Gallop
Russell Gallop

Reputation: 1699

Python argparse argument that is python keyword

I want to have a python command line argument --lambda, but I can't access it as lambda is a python keyword.

import argparse

p = argparse.ArgumentParser()
p.add_argument('--lambda')
args = p.parse_args()

print args.lambda

I get:

print args.lambda
                ^
SyntaxError: invalid syntax

How can I do this?

Upvotes: 2

Views: 353

Answers (2)

hpaulj
hpaulj

Reputation: 231605

argparse uses hasattr and getattr to set values in the Namespace. This allows you to use flags/dest that are not valid in the args.dest syntax. Here the problem is with a restricted key word. It could also be a string with special characters. So getattr(args, 'lambda') should work.

vars(args) creates a dictionary, allowing you to use vars(args)['lambda'].

But changing the dest is a cleaner solution. That's part of why that parameter is allowed.

(For a positional argument, choose a valid dest right away.)

Upvotes: 1

Russell Gallop
Russell Gallop

Reputation: 1699

You can add a different name for the attribute with dest e.g.

import argparse

p = argparse.ArgumentParser()
p.add_argument('--lambda', dest='llambda')
args = p.parse_args()

print args.llambda

Upvotes: 4

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