named parameter로 파이썬 구동하기(ex] python app.py --env=dev)

https://stackoverflow.com/questions/40001892/reading-named-command-arguments

33

Can I use argparse to read named command line arguments that do not need to be in a specific order? I browsed through the documentation but most of it focused on displaying content based on the arguments provided (such as --h).

Right now, my script reads ordered, unnamed arguments:

myscript.py foo-val bar-val

using sys.argv:

foo = sys.argv[1]
bar = sys.argv[2]

But I would like to change the input so that it is order agnostic by naming arguments:

myscript.py --bar=bar-val --foo=foo-val

python python-3.x arguments

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edited Oct 12 '16 at 15:01

asked Oct 12 '16 at 14:58

amphibient

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• cannot find a good duplicate, but check here for some examples: stackoverflow.com/questions/11415570/… – Jean-François Fabre♦ Oct 12 '16 at 15:01

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2 Answers

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42

You can use the Optional Arguments like so:

import argparse, sys

parser=argparse.ArgumentParser()

parser.add_argument('--bar', help='Do the bar option')
parser.add_argument('--foo', help='Foo the program')

args=parser.parse_args()

print args
print sys

Then if you call it with ./prog --bar=bar-val --foo foo-val it prints:

Namespace(bar='bar-val', foo='foo-val')
['Untitled 14.py', '--bar=bar-val', '--foo', 'foo-val']

Or, if the user wants help argparse builds that too:

 $ ./prog -h
usage: Untitled 14.py [-h] [--bar BAR] [--foo FOO]

optional arguments:
  -h, --help  show this help message and exit
  --bar BAR   Do the bar option
  --foo FOO   Foo the program

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edited Oct 12 '16 at 15:28

answered Oct 12 '16 at 15:22

dawg

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• I did not know that it was possible to use the --opt=val syntax. This is wonderful :) – Tryph Oct 12 '16 at 15:29
• 1
  how do I read the value of foo after the args have been loaded ? – amphibient Oct 12 '16 at 15:30
• is there like args.get('foo') ? – amphibient Oct 12 '16 at 15:30
• 4
  Use args.bar to read --bar It will return None if not included in the command. You can also use a default instead. – dawg Oct 12 '16 at 15:33 
• Using python 3.5.1, and when not included it doesn't return None; it gives an error. So as an alternative, d = vars(args) gives a dictionary (maps named arguments to values) – DZack Nov 13 '17 at 18:12 

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