Python argparse dict arg

Here's another solution using a custom action, if you want to specify dict key pairs together comma-separated --

import argparse
import sys
parser = argparse.ArgumentParser(description='parse key pairs into a dictionary')

class StoreDictKeyPair(argparse.Action):
     def __call__(self, parser, namespace, values, option_string=None):
         my_dict = {}
         for kv in values.split(","):
             k,v = kv.split("=")
             my_dict[k] = v
         setattr(namespace, self.dest, my_dict)

parser.add_argument("--key_pairs", dest="my_dict", action=StoreDictKeyPair, metavar="KEY1=VAL1,KEY2=VAL2...")

args = parser.parse_args(sys.argv[1:])
print args

Running:

python parse_kv.py --key_pairs 1=2,a=bbb,c=4 --key_pairs test=7,foo=bar

Output:

Namespace(my_dict={'1': '2', 'a': 'bbb', 'c': '4', 'test': '7', 'foo': 'bar'})

If you want to use nargs instead of comma-separated values in string:

class StoreDictKeyPair(argparse.Action):
     def __init__(self, option_strings, dest, nargs=None, **kwargs):
         self._nargs = nargs
         super(StoreDictKeyPair, self).__init__(option_strings, dest, nargs=nargs, **kwargs)
     def __call__(self, parser, namespace, values, option_string=None):
         my_dict = {}
         print "values: {}".format(values)
         for kv in values:
             k,v = kv.split("=")
             my_dict[k] = v
         setattr(namespace, self.dest, my_dict)

parser.add_argument("--key_pairs", dest="my_dict", action=StoreDictKeyPair, nargs="+", metavar="KEY=VAL")

args = parser.parse_args(sys.argv[1:])
print args

Running

python arg_test4.py --key_pairs 1=2 a=bbb c=4 test=7 foo=bar

Outputs:

values: ['1=2', 'a=bbb', 'c=4', 'test=7', 'foo=bar']
Namespace(my_dict={'1': '2', 'a': 'bbb', 'c': '4', 'test': '7', 'foo': 'bar'})

just another easy way:

parser = argparse.ArgumentParser()
parser.add_argument('--key1')
parser.add_argument('--key2')
args = parser.parse_args()
my_dict = args.__dict__

Python receives arguments in the form of an array argv. You can use this to create the dictionary in the program itself.

import sys
my_dict = {}
for arg in sys.argv[1:]:
    key, val=arg.split(':')[0], arg.split(':')[1]
    my_dict[key]=val

print my_dict

For command line:

python program.py key1:val1 key2:val2 key3:val3

Output:

my_dict = {'key3': 'val3', 'key2': 'val2', 'key1': 'val1'}

Note: args will be in string, so you will have to convert them to store numeric values.

I hope it helps.

I would use something like this:

p = argparse.ArgumentParser()
p.add_argument("--keyvalue", action='append',
               type=lambda kv: kv.split("="), dest='keyvalues')

args = p.parse_args("--keyvalue foo=6 --keyvalue bar=baz".split())
d = dict(args.keyvalues)

You could create a custom action which would "append" a parsed key-value pair directly into a dictionary, rather than simply accumulating a list of (key, value) tuples. (Which I see is what skyline75489 did; my answer differs in using a single --keyvalue option with a custom type instead of separate --key and --value options to specify pairs.)