[Solved] AttributeError: module 'argparse' has no attribute 'BooleanOptionalAction'

The argparse.BooleanOptionalAction feature is only available in Python 3.9 and above.

If you try to run this code in Python 3.8 and below.

parser = argparse.ArgumentParser(
    description='Description of my argument parser.')
parser.add_argument(
    '-f',
    '--feature',
    action=argparse.BooleanOptionalAction,
    default=False,
    help='Description of your feature.',
)

You'll get this error.

python script.py              
Traceback (most recent call last):
  File "script.py", line 12, in <module>
    action=argparse.BooleanOptionalAction,
AttributeError: module 'argparse' has no attribute 'BooleanOptionalAction'

In Python 3.8, you can do the following.

parser = argparse.ArgumentParser(
    description='Description of my argument parser.')
parser.add_argument(
    '-f',
    '--feature',
    action='store_true',
    help='Description of your feature.',
)

Let's see a complete example of how you'd use the --feature flag or its -f shorthand.

Example for Python 3.9.

# Python 3.9
# script.py
#!/usr/bin/env python
# coding: utf-8
import argparse

parser = argparse.ArgumentParser(
    description='Description of my argument parser.')
parser.add_argument(
    '-f',
    '--feature',
    action=argparse.BooleanOptionalAction,
    default=False,
    help='Description of your feature.',
)
opt = parser.parse_args()
print(opt.feature)

Example for Python 3.8.

# Python 3.8
# script.py
#!/usr/bin/env python
# coding: utf-8
import argparse

parser = argparse.ArgumentParser(
    description='Description of my argument parser.')
parser.add_argument(
    '-f',
    '--feature',
    action='store_true',
    help='Description of your feature.',
)
opt = parser.parse_args()
print(opt.feature)

Running the program

Then, here's what's returned when the script is executed on the command line.

python script.py
# False

python script.py --feature
# True

python script.py -f
# True

I hope that helped!