Passing arguments to a python program

Passing arguments to a Python program can be done using the command line when you run the program. Python provides the sys.argv list that contains the command-line arguments passed to the script.

Here's how you can pass and access command-line arguments in a Python program:

1. Using sys.argv:

pythonCopy code
import sys



# sys.argv[0] is the script name itself

script_name = sys.argv[0]

arguments = sys.argv[1:]  # Get all arguments excluding the script name



print("Script name:", script_name)

print("Arguments:", arguments)

You can run the script from the command line like this:

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python script.py arg1 arg2 arg3

1. Using argparse (Recommended for complex argument handling):

The argparse module provides a more structured and powerful way to handle command-line arguments. It allows you to define argument types, default values, descriptions, and more.

pythonCopy code
import argparse



parser = argparse.ArgumentParser(description='Process some arguments.')

parser.add_argument('arg1', type=int, help='First argument')

parser.add_argument('--arg2', type=str, default='default_value', help='Second argument (optional)')

parser.add_argument('--flag', action='store_true', help='Flag argument')



args = parser.parse_args()



print("arg1:", args.arg1)

print("arg2:", args.arg2)

print("flag:", args.flag)

You can run the script with arguments:

bashCopy code
python script.py 123 --arg2 custom_value --flag

1. Using sys.stdin (Piping input):

You can also pass input to the script using pipes and sys.stdin. This is useful when you want to pass data from one command to another.

bashCopy code
echo "Hello, World!" | python script.py

In your Python script:

pythonCopy code
import sys



data = sys.stdin.read()

print("Input data:", data)

These are some common ways to pass arguments to a Python program. Depending on your needs, you can choose the appropriate method. If you have complex argument handling requirements, using the argparse module is recommended.