problem in output of a snippet code

[akbarza]

hi
assume the below snippet code(the code address is in the docstring of the code) :

 '''
from:https://www.knowledgehut.com/blog/programming/sys-argv-python-
examples#what-is-%22sys.%C2%A0argv%C2%A0[1]%22?-how-does%C2%A0it-work?%C2%A0
'''

import getopt
import sys
 
first =""
last =""
argv = sys.argv[1:]
try:
    options, args = getopt.getopt(argv, "f:l:",
                               ["first =",
                                "last ="])
except:
    print("Error Message ")
 
for name, value in options:
    if name in ['-f', '--first']:
        first = value
    elif name in ['-l', '--last']:
        last = value
 
print(first + " " + last)

# in cmd write: python getopt_module.py -f Knowledge -l Hut
# or
# in cmd write: python getopt_module.py --first Knowledge --last Hut
#### but the last line does not show anything in output, why?

after saving this file as getopt_module.py, if I write in cmd:

python getopt_module.py -f Knowledge -l Hut

The output will be:

Output:
Knowledge Hut

but if write in cmd:

python getopt_module.py --first Knowledge --last Hut

then nothing will be in the output. why?
thanks

[snippsat]

Do not use getop.

PEP 387 defines "Soft Deprecation", getopt and optparse are soft deprecated

In stander library use argparse.
So if rewrite it look like this:

# file: arg_ex.py
import argparse

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('-f', '--first', type=str, help='First name')
parser.add_argument('-l', '--last', type=str, help='Last name')
args = parser.parse_args()

# Use the arguments
first = args.first if args.first else ""
last = args.last if args.last else ""
print(f'{first} {last}')

Usage command line:

Output:
λ python arg_ex.py --help
usage: arg_ex.py [-h] [-f FIRST] [-l LAST]

Get Names

options:
  -h, --help            show this help message and exit
  -f FIRST, --first FIRST
                        First name
  -l LAST, --last LAST  Last name

C:\code\cv_test
λ python arg_ex.py -f Tom
Tom

C:\code\cv_test
λ python arg_ex.py --first Kent --last Superman
Kent Superman

---

There are also good 3-party libraries for this like eg Typer
To show a example that i posted before.

# file: rename_files.py
from pathlib import Path
import typer

app = typer.Typer()

@app.command()
def renameit(
    old_name: str = typer.Option(..., '-o', '--old-name'),
    new_name: str = typer.Option(..., '-n', '--new-name'),
):
    old_path = Path(old_name)
    if old_path.is_file():
        old_path.rename(Path(new_name))
        typer.echo(f'File renamed from {old_name} to {new_name}')
    else:
        typer.echo('File not found.')

if __name__ == '__main__':
    app() 

Using it,see that help and colors(use Rich under the hood) get generated automatic.

[deanhystad]

This line was wrong.

options, args = getopt.getopt(argv, "f:l:", ["first =", "last ="])

It should be

options, args = getopt.getopt(argv, "f:l:", ["first=", "last="])

from getopt import getopt

def getargs(argv):
    options, args = getopt(argv, "f:l:", ["first=", "last="])
    options = dict(options)
    return (
        options.get('--first', options.get('-f')),
        options.get('--last', options.get('-l')),
        *args
    )

print(getargs("-f Knowledge -l Hut".split()))
print(getargs("--first Knowledge --last Hut".split()))
print(getargs("-f Knowledge --last Hut".split()))
print(getargs("-f Knowledge --last Hut arg1 arg2".split()))

Output:
('Knowledge', 'Hut')
('Knowledge', 'Hut')
('Knowledge', 'Hut')
('Knowledge', 'Hut', 'arg1', 'arg2')