What is the right way to treat Python argparse.Namespace() as a dictionary?

python

namespace

argparse

dictionary

byAnton Shumikhin·Mar 12, 2025

If you're in haste and just want a quick way to convert argparse.Namespace() into a dictionary, use vars(). It allows you to handle arguments like a dictionary:

import argparse

# Baking a parser and adding ingredients
parser = argparse.ArgumentParser()
parser.add_argument('--foo', type=int)

# Baking time! Seal arguments into a dictionary
args = parser.parse_args()
args_dict = vars(args)

# Gotta taste it now! Also sure to taste good even if not identical
value = args_dict.get('foo', 'default_value')

Sneaky Tip: Go with args_dict.get('key', 'default_value') to avoid KeyError, just like using a GPS to avoid getting lost on the road.

If you are a safe rider, befriend hasattr() to check if the road ahead exists and getattr() to keep moving on the right path with Namespace:

# Safe riding with hasattr() and getattr()
if hasattr(args, 'foo'):
    value = getattr(args, 'foo')
else:
    value = 'default_value'

You're now a sheepdog ensuring your Namespace sheep don't go astray.

The Fairy Godmother: vars() Function

vars() is the fairy godmother that transforms any object, yes, even Cinderella's carriage like argparse.Namespace, into a charming prince of a dictionary. Totally official and standard.

Don't Trespass: dictProperty

Although __dict__ can be conjured to access Namespace, keep off the grass. Use footpaths like vars() to keep the property clean and protected.

Before You Hallucinate Namespace into a Dict

Check if you really need to transform argparse.Namespace into a dictionary. If your method smiles at a dictionary object, you have the green light. But for other events, just play with the attributes:

# Direct attribute party
foo_value = args.foo

Turn Your Namespace into a Dict, When...

... such a behavior feels appropriate. Like when a function demands a dictionary input, merging command-line arguments with other dictionary playmates is needed, or the Namespace needs a makeover for saving to a file.

Spontaneous Argument Scenarios

In a mystical land where arguments come unannounced, you can't set up all potential keys. Fret not, let vars() handle the surprise guests.

# Mysterious talents showcasing post-parsing
setattr(args, 'dynamic_arg', 'value')
args_dict = vars(args)
# 'dynamic_arg' is now partying with others inside the dictionary

Wishing Namespace Back from Dict

If you have a dict and yearn for argparse.Namespace(), make a wish and see it come true!

new_namespace = argparse.Namespace(**your_dict)

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Safe Navigation through Namespace The Fairy Godmother: vars() Function Don't Trespass: __dict__Property Before You Hallucinate Namespace into a Dict Turn Your Namespace into a Dict, When...Spontaneous Argument Scenarios Wishing Namespace Back from Dict