I'm new to python and want to handle variable number of arguments for a python code such that a string like this can be handled -
python abc.py -20 input1.txt input2.txt .. output.txt
-20 is optional. There has to be at least one input file, but there can be any number of those and a necessary output file at the end. I looked at argparse, and I can do fixed arguments or optional but unable to figure it out for this case.
Add nargs='+' for variable number arguments.
parser.add_argument("input", nargs='+')
parser.add_argument("output")
$ ./test.py input1 input2 input3 output
Namespace(input=['input1', 'input2', 'input3'], output='output')
Use argparse. Here's an example from argparse docs:
import argparse
parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('integers', metavar='N', type=int, nargs='+',
help='an integer for the accumulator')
parser.add_argument('--sum', dest='accumulate', action='store_const',
const=sum, default=max,
help='sum the integers (default: find the max)')
args = parser.parse_args()
print(args.accumulate(args.integers))
Run:
$ prog.py 1 2 3 4
4
$ prog.py 1 2 3 4 --sum
10
-20signify? With something this simple, just looking atsys.argvmight be good enough ...argparse, but if you don't mind to change the CLI into a more standard format, it will be easy.