Input the Filename in the Commandline as an Argument in Python [Closed]

Question

I want to do the modification in my code such that I am able to input my file in the same command line where I’m calling python code like:

script.py filename

Presently my code is:

filename = raw_input('Enter a filename: ')
with open(filename) as f:
   next(f)
   for lines in f:

Please suggest me how should I proceed with the same.

Accepted Answer

I would use sys.argv.

import sys
filename = sys.argv[1]

sys.argv will be a list of elements in your call.

Answer 2

sys.argv is the easiest for a simple use case.

For more advanced uses you could use argparse, but I'd prefer click (“Command Line Interface Creation Kit”) which makes creating command line tools with Python really easy:

import click
@click.command()
@click.argument('filename', type=click.Path(exists=True, readable=True), nargs=1)
def main(filename):
    ...

main()

using @click.option() you can also create custom flags such as --filename.

This makes using arguments much easier, as you can define input types that get checked automatically. It also produces nice error messages and with --help it prints usage information:

Usage: test.py [OPTIONS] FILENAME

Options:
  --help  Show this message and exit.

You will need to install click:

# Python2:
pip install click

# Python3:
pip3 install click

Answer 3

Use sys module:

import sys
with open(sys.argv[1]) as filename:
        for line in filename:
               print(line)

See also How to read/process command line arguments? for usage of argparse module to create custom flags such as -f <filename>

Input the Filename in the Commandline as an Argument in Python [Closed]

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3 Answers

Chloe Bennett