I want to pass 2 lists of integers as input to a python program.
For e.g, (from command line)
python test.py --a 1 2 3 4 5 -b 1 2
The integers in this list can range from 1-50, List 2 is subset of List1.
Any help/suggestions ? Is argparse
the right module ? Any concerns in using that ?
I have tried :
import argparse
if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument('--a', help='Enter list 1 ')
parser.add_argument('--b', help='Enter list 2 ')
args = parser.parse_args()
print (args.a)
argparse
supports nargs
parameter, which tells you how many parameters it eats.
When nargs="+"
it accepts one or more parameters, so you can pass -b 1 2 3 4
and it will be assigned as a list to b
argument
# args.py
import argparse
p = argparse.ArgumentParser()
# accept two lists of arguments
# like -a 1 2 3 4 -b 1 2 3
p.add_argument('-a', nargs="+", type=int)
p.add_argument('-b', nargs="+", type=int)
args = p.parse_args()
# check if input is valid
set_a = set(args.a)
set_b = set(args.b)
# check if "a" is in proper range.
if len(set_a - set(range(1, 51))) > 0: # can use also min(a)>=1 and max(a)<=50
raise Exception("set a not in range [1,50]")
# check if "b" is in "a"
if len(set_b - set_a) > 0:
raise Exception("set b not entirely in set a")
# you could even skip len(...) and leave just operations on sets
# ...
So you can run:
$ python arg.py -a 1 2 3 4 -b 2 20
Exception: set b not entirely in set a
$ python arg.py -a 1 2 3 4 60 -b 2
Exception: set a not in range [1,50]
And this is valid:
$ python arg.py -a 1 2 3 4 -b 2 3
You can pass them as strings than convert to lists. You can use argparse or optparse.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--l1', type=str)
parser.add_argument('--l2', type=str)
args = parser.parse_args()
l1_list = args.l1.split(',') # ['1','2','3','4']
Example: python prog.py --l1=1,2,3,4
Also,as a line you can pass something like this 1-50 and then split on '-' and construct range. Something like this:
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--l1', type=str, help="two numbers separated by a hyphen")
parser.add_argument('--l2', type=str)
args = parser.parse_args()
l1_list_range = xrange(*args.l1.split('-')) # xrange(1,50)
for i in l1_list_range:
print i
Example: python prog.py --l1=1-50
Logic I think you can write yourself. :)
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