Python 3: `else` statement get executed even `if` statement was true

Question

According to previous question Else statement executing even the IF statement is TRUE the suggestion provided was to check the indention. Indention seems to be correct in my code. What seems to be the problem?

According to https://www.tutorialspoint.com/python/python_if_else.htm

An else statement can be combined with an if statement. An else statement contains the block of code that executes if the conditional expression in the if statement resolves to 0 or a FALSE value.

As per my understanding, else should not be executed if the if statement is correct/True.

However, in this code ... else statement still get executed .. see python myCode.py -i 8.8.8.8

C:\Python>python myCode.py
No Argument Provided


C:\Python>python myCode.py -h
usage: myCode.py [-h] [-u URL] [-i IP]

optional arguments:
  -h, --help         show this help message and exit
  -u URL, --url URL  Uniform Resource Locator
  -i IP, --ip IP     IP Address


C:\Python>python myCode.py -u google.com
~ URL is google.com


C:\Python>python myCode.py -i 8.8.8.8
~ IP Address is 8.8.8.8
No Argument Provided

C:\Python>

This is the code.

import argparse

parser = argparse.ArgumentParser()

parser.add_argument('-u', '--url',
    help='Uniform Resource Locator' )

parser.add_argument('-i', '--ip',
    help='IP Address' )

args = parser.parse_args()

if args.ip:
    print("~ IP Address is " + args.ip)
if args.url:
    print("~ URL is " + args.url)
else:
    print("No Argument Provided")

Please let me know what went wrong here. No Argument Provided is not supposed to be there.

C:\Python>python myCode.py -i 8.8.8.8
~ IP Address is 8.8.8.8
No Argument Provided

'else' refers to the last `if`, so if you provide an IP but no URL the else-part is executed. — Matthias, Dec 20 '18 at 07:36

score 6 · Accepted Answer · answered Dec 20 '18 at 07:35

6

You probably need to use elif. The else in your case is executed because args.url is empty.

Ex:

if args.ip:
    print("~ IP Address is " + args.ip)
elif args.url:
    print("~ URL is " + args.url)
else:
    print("No Argument Provided")

answered Dec 20 '18 at 07:35

Rakesh

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Rakesh 's answer is right but besides that, there is a more elegant solution for the underneath problem, see: https://docs.python.org/3/library/argparse.html#mutual-exclusion – Melih Taşdizen Dec 20 '18 at 07:57

Python 3: `else` statement get executed even `if` statement was true

1 Answers1