Parsing boolean values with argparse
I would like to use argparse to parse boolean command-line arguments written as "--foo True" or "--foo False". For example:
my_program --my_boolean_flag False
However, the following test code does not do what I would like:
import argparse
parser = argparse.ArgumentParser(description="My parser") parser.add_argument("--my_bool", type=bool)
cmd_line = ["--my_bool", "False"]
parsed_args = parser.parse(cmd_line)
Sadly, parsed_args.my_bool evaluates to True. This is the case even when I change cmd_line to be ["--my_bool", ""], which is surprising, since bool("") evaluates to False.
How can I get argparse to parse "False", "F", and their lower-case variants to be False?
Answer (1)
import argparse
# Custom function to parse boolean values
def parse_boolean(value):
if value.lower() in ['true', '1', 't', 'y', 'yes']:
return True
elif value.lower() in ['false', '0', 'f', 'n', 'no']:
return False
else:
raise argparse.ArgumentTypeError(f"Invalid boolean value: {value}")
# Setup the argument parser
parser = argparse.ArgumentParser(description="My parser")
parser.add_argument("--my_bool", type=parse_boolean)
# Example command-line input (this would be passed as sys.argv in a real case)
cmd_line = ["--my_bool", "False"]
# Parse the arguments
parsed_args = parser.parse_args(cmd_line)
# Out
To achieve the behavior you're describing, where --my_bool False is parsed as a boolean False geometry dash lite, and --my_bool True is parsed as a boolean True, you need to implement a custom type or a custom action in argparse.