I have a python program that takes in many arguments and run. With argparse, I can define the arguments, their default values, their explanations, and it can be used as a convenient container. So it's all good for passing arguments from command line.
But can I also use it to pass the arguments from code, for API call?
Yes, certainly argparse can be used to pass arguments both from command line and from code.
For example:
import argparse
# Define default values
parser = argparse.ArgumentParser()
parser.add_argument('--foo', default=1, type=float, help='foo')
# Get the args container with default values
if __name__ == '__main__':
args = parser.parse_args() # get arguments from command line
else:
args = parser.parse_args('') # get default arguments
# Modify the container, add arguments, change values, etc.
args.foo = 2
args.bar = 3
# Call the program with passed arguments
program(args)
parse_args([]) is better (equivalent to an empty sys.argv[1:] list).With vars() you can use your args like dictionaries.
from argparse import ArgumentParser
parser = ArgumentParser()
parser.add_argument("-f", "--foo")
parser.add_argument("-b", "--bar")
args = vars(parser.parse_args())
print(f"args foo is {args['foo']}")
print(f"args bar is {args['bar']}")
Result when you execute and parse some arguments look like.
python3 test.py --foo cat --bar dog
args foo is cat
args bar is dog
from argparse import ArgumentParser
parser = ArgumentParser()
parser.add_argument("-f", "--file", dest="filename",
help="write report to FILE", metavar="FILE")
parser.add_argument("-q", "--quiet",
action="store_false", dest="verbose", default=True,
help="don't print status messages to stdout")
args = parser.parse_args()
When running this file from terminal, you can pass the arguments in the following manner:
python36 commandline_input.py 10
python36 commandline_input.py 10 --foo 12
The first positional argument is mandatory, the second is optional therefore you need a flag (--foo).
commandline_input.py:
import argparse
def main(mandatory_arg, optional_arg):
# your program
pass
if __name__ == '__main__':
parser = argparse.ArgumentParser()
# mandatory
parser.add_argument('bar', help='Some Bar help')
# optional
parser.add_argument('-f', '--foo', default='default foo value',
help='Some foo help')
args = parser.parse_args()
# mandatory args
print(args.bar, '(man)')
# optional args
if args.foo:
print(args.foo, '(opt)')
# your API call
main(args.bar, [args.foo])
argsNamespaceobject created byparse_args(). You can recreate that directly, e.g.args = argparse.Namespace(foo='bar', arg1=12), etc.