Boolean argument for script

Question

In Python, I understand how int and str arguments can be added to scripts.

parser=argparse.ArgumentParser(description="""Mydescription""")
parser.add_argument('-l', type=str, default='info', help='String argument')
parser.add_argument('-dt', type=int, default ='', help='int argument')

What is it for booleans?

Basically I want to pass a flag into my script which will tell the script whether to do a specific action or not.

What behavior do you want with booleans? (say, with '-v true' and '-v false'?) — kennytm, Feb 07 '12 at 21:11

sberry · Accepted Answer · 2014-02-28T20:07:14.963

157

You can either use the action with store_true|store_false, or you can use an int and let implicit casting check a boolean value.

Using the action, you wouldn't pass a --foo=true and --foo=false argument, you would simply include it if it was to be set to true.

python myProgram.py --foo

In fact I think what you may want is

parser.add_argument('-b', action='store_true', default=False)

edited Feb 28 '14 at 20:07

answered Feb 07 '12 at 21:11

sberry

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I don't believe `default=False` is necessary. – Paul Draper Jan 20 '14 at 01:16
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@PaulDraper: Explicit is better than implicit. – sberry Feb 28 '14 at 20:06
@PaulDraper I've checked that it isn't needed, but you can put it as an explicit value. – Caumons Sep 30 '14 at 10:10
@PaulDraper Isn't the default for boolean True? – aerin Aug 28 '18 at 22:03

score 20 · Answer 2 · answered Feb 07 '12 at 21:11

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parser.add_argument('--foo', action='store_true')

answered Feb 07 '12 at 21:11

Ned Batchelder

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ThorSummoner · Answer 3 · 2017-08-24T20:02:06.833

import distutils.util
ARGP.add_argument('--on', '-o', type=distutils.util.strtobool, default='true')

Example calling it:

$ ./myscript                # argp.on = 1
$ ./myscript --on=false     # argp.on = 0
$ ./myscript --on=False     # argp.on = 0
$ ./myscript --on=0         # argp.on = 0
$ ./myscript --on=1         # argp.on = 1
$ ./myscript -o0            # argp.on = 0
$ ./myscript -o false       # argp.on == 0

i should mention, you can bind the argument to a local wrapper function too, to handle some other exact string matching if you want to support values like "yes" and "no". you can also try interpreting the input as yaml, which can handle yes/no too. i haven't done this in a while though, and i think lately I've suck to mutually exclusive arguments with the same dest value, one --no-option with action='store_false', and one --option with action='store_true'

BEST OPTION! -- it allows to put all types of True/False indicators like True/true/1/Y/y/Yes/yes and will return an error if you try to put invalid string like "BlaBlaBla" — sebtac, Sep 30 '21 at 19:31

Boolean argument for script

3 Answers3

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