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Pass arguments via file and via command line [duplicate]

I want to launch my script like this:
python3 main.py #params.conf 1 2
where params.conf is a file and 1, 2 are string arguments.
I know how to parse file alone:
argparser = ArgumentParser()
argparser.add_argument('arg1', help='heeelp')
...
args = argparser.parse_args()
But how to parse following arguments?

An argument prefixed with # is treated as if its contents were in the command line directly, one argument per line. So if the contents of params.confis
2
3
And you define a parser like
import argparse
p = argparse.ArgumentParser(fromfile_prefix_chars='#')
p.add_argument("a")
p.add_argument("b")
p.add_argument("c")
p.add_argument("d")
args = p.parse_args()
and you call your script as
script.py 1 #params.conf 4
then your arguments a through d will be set to 1 through 4, respectively.

You just add more argparser.add_argument calls.
Like this:
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('arg1', type=str)
parser.add_argument('arg2', type=str)
parser.add_argument('arg3', type=str)
args = parser.parse_args()
print(args) # arguments are parsed

python get changed (non-default) cli arguments?

Given an argument parser with n arguments, where I change the default value of only a small subset every run from the command line, is there a clean way of extracting a dict/namespace of all the non-default k,v arguments?
parser = argparse.ArgumentParser()
parser.add_argument("--a",type=str,default='a')
parser.add_argument("--b",type=str,default='b')
parser.add_argument("--c",type=str,default='c')
parser.add_argument("--d",type=str,default='d')
And
python run.py --a "e"
I would like to have
def main():
parser = argparse.ArgumentParser()
parser.add_argument("--a",type=str,default='a')
parser.add_argument("--b",type=str,default='b')
parser.add_argument("--c",type=str,default='c')
parser.add_argument("--d",type=str,default='d')
non_default = parse_non_default(parser) # non_default = {'a':'e'}

You could lookup the parser and compare which values differenciate:
import argparse
def main():
parser = argparse.ArgumentParser()
parser.add_argument("--a", type=str, default='a')
parser.add_argument("--b", type=str, default='b')
parser.add_argument("--c", type=str, default='c')
parser.add_argument("--d", type=str, default='d')
parser.add_argument("--n", type=int, default=999)
args = parser.parse_args(['--a', 'e']) # Test CLI arguments!
non_default = {
opt.dest: getattr(args, opt.dest)
for opt in parser._option_string_actions.values()
if hasattr(args, opt.dest) and opt.default != getattr(args, opt.dest)
}
print(non_default)
main()
Out:
{'a': 'e'}

argparse - how to pass argument from args into function?

import argparse
from queries import most_common_cities
parser = argparse.ArgumentParser(description='A script that does operations with database data and returns values')
parser.add_argument('-c', '--most_common_cities',
nargs=1,
type=positive_int,
help='Specify how many common cities.')
args = parser.parse_args()
if args.most_common_cities:
result = most_common_cities(n) # "n" should be an arg passed by user
print(result)
How could I pass arguments from CLI to my function arg?
When someone use command:
python argp.py --most_common_cities 5
It should return 5 most common cities.

Remove nargs=1, then args.most_common_cities will be the actual value passed in.
nargs=1 wraps it in a list.
parser.add_argument('-c', '--most_common_cities',
type=int,
help='Specify how many common cities.')
args = parser.parse_args(['-c', '5'])
n = args.most_common_cities
print(n)
print(type(n))
# 5
# <class 'int'>

I started your script with following command:
python3 test.py --most_common_cities 5
You can access the arguments with:
import argparse
parser = argparse.ArgumentParser(description='A script that does operations with database data and returns values')
parser.add_argument('-c', '--most_common_cities',
nargs=1,
type=int,
help='Specify how many common cities.')
args = parser.parse_args()
arguments = vars(parser.parse_args())
print(arguments) #{'most_common_cities': [5]}
#then you can access the value with:
arguments['most_common_cities']

Python argparse; if argument 1 not present, how to continue and set required next arguments

I have 3 arguments in my python script. Two are required for running the script and argument 1 shows only a list of options.
I want that if argument 1 is set, that argument 2 and 3 are not required anymore, and if argument 1 is not used, that argument 2 and 3 are required.
The arguments are as follows:
parser = argparse.ArgumentParser()
parser.add_argument("--1", help="list of options", action="store_true", default=False)
parser.add_argument("--2", help="level", required=True)
parser.add_argument("--3", help="folder", required=True)
args = parser.parse_args()
I tried it with the following command:
parser = argparse.ArgumentParser()
parser.add_argument("--1", help="list of options", action="store_true", default=False)
parser.add_argument("--2", help="level)
parser.add_argument("--3", help="folder")
args = parser.parse_args()
if args.1:
print('list of options')
sys.exit()
if not args.1:
parser = argparse.ArgumentParser()
parser.add_argument("--1", help="list of options", action="store_true", default=False)
parser.add_argument("--2", help="level", required=True)
parser.add_argument("--3", help="folder", required=True)
But the problem than is that if the user only set option 2 (or only option 3), that the script continues, instead of having both options 2 and 3 required.
Is it possible in Python to first test for option 1 and, if this option is not set, continue to test for option 2 and 3, and set these two as required?

Selected options activate right subparsers

I have to invoke my script in this way.
script.py multiple --ways aa bb -as abab -bs bebe
In this case -as abab reffers to "aa" option from --ways parameter and -bs bebe to "bb" option.
And all chosed options should affect what "fulfill" method will be used.
If we chose 'aa' and 'bb' there should only be options '-as' and '-bs' not '-cs'.
import sys
from argparse import ArgumentParser
def fulfill_aa_parser(aa_parser):
aa_parser.add_argument('--ass', '-as', type=str, required=True, choices=['abababa'])
def fulfill_bb_parser(aa_parser):
aa_parser.add_argument('--bass', '-bs', type=str, required=True, choices=['bebebe'])
def fulfill_cc_parser(aa_parser):
aa_parser.add_argument('--cass', '-cs', type=str, required=True, choices=['cycycyc'])
def fulfill_multiple_parser(multiple_parser):
multiple_parser.add_argument('--ways', '-w', type=str, choices=['aa','bb', 'cc'], nargs='+', required=True)
def main(argv):
parser = ArgumentParser(description='TEST CASE')
subparsers = parser.add_subparsers(dest='type')
multiple_parser = subparsers.add_parser(
'multiple'
)
aabbparsers = multiple_parser.add_subparsers()
aa_parser = aabbparsers.add_parser('aa')
bb_parser = aabbparsers.add_parser('bb')
cc_parser = aabbparsers.add_parser('cc')
fulfill_multiple_parser(multiple_parser)
fulfill_aa_parser(aa_parser)
fulfill_bb_parser(bb_parser)
fulfill_cc_parser(cc_parser)
args = parser.parse_args(argv)
if args.type is None:
parser.print_help()
return
if __name__ == '__main__':
main(sys.argv[1:])
Parsing this in this way:
fulfill_aa_parser(multiple_parser)
fulfill_bb_parser(multiple_parser)
fulfill_cc_parser(multiple_parser)
will lead to parser always asking for '-as', '-bs' ,'-cs' and options in '--ways' will not affect this
EDIT : \
This is it looks when there is some thought put to it.
Just simply pass parser to this function
def fulfill_apple_argparser(parser):
parser.add_argument("--apple_argument")
def fulfill_banana_argparser(parser):
parser.add_argument("--banana_argument")
def fulfill_peach_argparser(parser):
parser.add_argument("--peach_argument")
def many_fruits_parse(parser, progs=None, list_of_fruits=('apple', 'banana', 'peach')):
progs = progs or []
if len(list_of_fruits) == 0 or parser in progs:
return
fulfill = {'apple': fulfill_apple_argparser, 'banana': fulfill_banana_argparser,
'peach': fulfill_peach_argparser}
subparsers = parser.add_subparsers(title='subparser', dest=parser.prog)
progs.append(parser)
for fruit in list_of_fruits:
secondary = [x for x in list_of_fruits if x != fruit]
fruit_parser = subparsers.add_parser(fruit, help=fruit)
fulfill[fruit](fruit_parser)
many_fruits_parse(fruit_parser, progs, secondary)

add_subparsers creates a special kind of positional argument, one that uses the add_parser command to create choices. Once a valid choice is provided, parsing is passed to that parser.
With
script.py multiple --ways aa bb -as abab -bs bebe
parser passes the task to multiple_parser. The --ways optional then gets 2 values
Namespace(ways=['aa','bb'])
Neither of those strings is used as a value for aabbparsers, and multiple_parser doesn't know what to do with '-as` or '-bs', and (I expect) will raise an error.
With:
script.py multiple aa -as abab
parsing is passed from parser to multiple_parser to aa_parser, which in turn handles '-as abab', producing (I think)
Namespace(as='abab')
Nesting as you do with multiple and aa is the only way to use multiple subparsers. You can't have two subparses 'in-parallel' (e.g. 'aa' and 'bb').
Especially when testing it's a good idea to provide a dest to the add_subparsers command. It gives information on which subparsers is being invoked.