Why error is thrown when a code is put inside function?

Question

I trying to write a script but I don't understand the following behavior.

Let's say I have script.py containing

import sys
import subprocess

result = subprocess.run(["flatpak", "list", "--columns=application", "--app"], check=True, stdout=subprocess.PIPE)
somestring = str(result.stdout, 'utf-8')
print(somestring)

And from interactive shell I run :

>>> import script

This works perfectly.

But then, if I have this file instead (called func.py) :

import sys
import subprocess

def GetInstalledApps():
  result = subprocess.run(["flatpak", "list", "--columns=application", "--app"], check=True, stdout=subprocess.PIPE)
  somestring = str(result.stdout, 'utf-8')
  print(somestring)

If I jump into python interactive shell and run

>>> import func # this call succeed
>>> func.GetInstalledApps() # this throw the following error :
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/path/to/func.py", line 11, in GetInstalledApps
    somestring = str(result.stdout, 'utf-8')
           ^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: a bytes-like object is required, not 'str'

I understand what the error means, but I don't understand it is thrown.

did you run import func in an interactive shell that had ALREADY imported func? if so, try again in a new shell — soundstripe
– soundstripe, Commented Aug 7, 2023 at 15:06
from comand line, I type python. My python version is 3.11.4 — Gwendal
– Gwendal, Commented Aug 7, 2023 at 15:07
@soundstripe, already tried. And even without relaunching the shell it seems to update when I modify the imported file — Gwendal
– Gwendal, Commented Aug 7, 2023 at 15:09
Ok I fixed the issue. I post will post an answer and close this question — Gwendal
– Gwendal, Commented Aug 7, 2023 at 15:11

Gwendal · Accepted Answer · 2023-08-07 15:15:32Z

0

I fixed this issue.

I tried making this script file (called myscript.sh) :

#!/usr/bin/python

import func

func.GetInstalledApps()

Then, if from command line (bash shell) I run :

./myscript.sh

It works. The remaining issue to figure out is why the code does not work from python interactive shell ?

answered Aug 7, 2023 at 15:15

Gwendal

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3 Comments

Barmar Over a year ago

This doesn't answer the question, it just avoids the problem.

Abdul Aziz Barkat Over a year ago

A script file doesn't really need to have a .sh extension... Naming your file that way is semantically wrong since your file is actually a Python file. You can name it myscript.py and it will work completely fine.

Gwendal Over a year ago

@Barmar A workaround is sometimes enough... But I would gladly know why it is not working in interactive shell.

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