Python packages.'import sys' vs 'from sys import argv'

Question

I'm trying to use 'argv' into my python script. For this i'm using following code:

from sys import argv
script, file_name = argv
print(file_name)

python3 e.py e.txt This code works fine.

But when I use:

import sys

and try to use 'argv', I get error:

'NameError: name 'argv' is not defined '.

I don't understand this as by importing 'sys' full module becomes usable into my code.

Can you explain why does this happen? How to packages work?

Thank you.

Answer 1

Import sys does not give you direct access to any of the names inside sys itself To access those you need to prefix them with sys:

sys.argv
sys.exit()

If you want use argv instead sys.argv try

from sys import *