How to accept boolean value from command line using argparse module of Python

Question

I want to pass boolean values (True/False) from the command line using argparse module, but the value is treated as a string. I am using the following way to pass boolean values. How can I make it work?

parser.add_argument("-trim_results", type=bool, choices=[True, False], default=True,

                help="want to trim the results?")

Answer 1

"type=bool" is not recommended as the bool() function converts empty strings to False and non-empty strings to True. You can use a user-defined function as a type to convert a string to a boolean value.

Here is an example:

def str_to_bool(s):

    """

    convert command line True/False to boolean as argparse considers them string.

    """

    if s == 'True':

        return True

    elif s == 'False':

        return False

    else:

        print("invalid boolean value provided")

        

parser.add_argument("-trim_results", type=str_to_bool, choices=[True, False], default=True,

                help="want to trim the results")