python argh/argparse: How can I pass a list as a command-line argument?

Question

I'm trying to pass a list of arguments to a python script using the argh library. Something that can take inputs like these:

./my_script.py my-func --argA blah --argB 1 2 3 4 ./my_script.py my-func --argA blah --argB 1 ./my_script.py my-func --argA blah --argB  

My internal code looks like this:

import argh  @argh.arg('--argA', default="bleh", help='My first arg') @argh.arg('--argB', default=[], help='A list-type arg--except it\'s not!') def my_func(args):     "A function that does something"      print args.argA     print args.argB      for b in args.argB:         print int(b)*int(b)  #Print the square of each number in the list     print sum([int(b) for b in args.argB])  #Print the sum of the list  p = argh.ArghParser() p.add_commands([my_func]) p.dispatch() 

And here's how it behaves:

$ python temp.py my-func --argA blooh --argB 1 blooh ['1'] 1 1  $ python temp.py my-func --argA blooh --argB 10 blooh ['1', '0'] 1 0 1  $ python temp.py my-func --argA blooh --argB 1 2 3 usage: temp.py [-h] {my-func} ... temp.py: error: unrecognized arguments: 2 3 

The problem seems pretty straightforward: argh is only accepting the first argument, and treating it as a string. How do I make it "expect" a list of integers instead?

I see how this is done in optparse, but what about the (not-deprecated) argparse? Or using argh's much nicer decorated syntax? These seem much more pythonic.

Answer 1

With argparse, you just use type=int

import argparse  parser = argparse.ArgumentParser() parser.add_argument('-a', '--arg', nargs='+', type=int) print parser.parse_args() 

Example output:

$ python test.py -a 1 2 3 Namespace(arg=[1, 2, 3]) 

Edit: I'm not familiar with argh, but it seems to be just a wrapper around argparse and this worked for me:

import argh  @argh.arg('-a', '--arg', nargs='+', type=int) def main(args):     print args  parser = argh.ArghParser() parser.add_commands([main]) parser.dispatch() 

Example output:

$ python test.py main -a 1 2 3 Namespace(arg=[1, 2, 3], function=<function main at 0x.......>)