Calling command line arguments in Python 3

Question

I am writing a program in Python 3 that will take data from a csv file, make adjustments to it and write the new data to a csv file that will be named by the user.

I'm just trying to understand the command line part. I want it to execute properly in this format.

$ program.py input.csv output.csv

I plan to also make it check that there are 3 total arguments.

My question is where do this filename inputs on the command line go? Are they saved to a default variable? How can I call these filenames within my python program?

Answer 1

Command line options are stored in sys.argv. You may want to check this:

http://docs.python.org/3/library/sys.html?highlight=argv#sys.argv

Beside, if you need more complex command-line argument parsing and deciding your program logic based on that, you should try argparse

• Manmohan Singh: For calling these filenames, you already have sys.popen, os.system, subprocess modules.