The imported modules get unimported after running a python file

Question

I noticed that all the modules I import are removed (I can't use them anymore without importing them again) after I run a python file in the python IDE. Here is the view of my IDE:

Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> import os
>>> os
<module 'os' from 'C:\\Users\\MN\\AppData\\Local\\Programs\\Python\\Python37\\lib\\os.py'>
>>> 
 RESTART: C:/Users/MN/AppData/Local/Programs/Python/Python37/python file just ran.py 
A python file just ran
>>> os
Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    os
NameError: name 'os' is not defined
>>>

For deep view, this was in my file:

print("A python file just ran")

Why is this happening and how to make the imported modules stay in there without importing them again?

What IDE is this? How do you run the script, with a menu option in the iDE? The output you show tells you the Python interpreter was restarted, so clearly was run from a clean slate. — Martijn Pieters, Aug 19 '19 at 10:45
@MartijnPieters It is already clear that I am using Python IDE. I have also written that in the post. I run my script by pressing `f5`. — Nouman, Aug 19 '19 at 11:28
Perhaps you mean `IDLE`? “Python IDE” is too generic a name. Running a script with F5 runs the script in a new process, you can’t access a preexisting console namespace. — Martijn Pieters, Aug 19 '19 at 12:32
E.g. see [What does "== RESTART ==" in the IDLE Shell mean?](https://stackoverflow.com/q/38627504). — Martijn Pieters, Aug 19 '19 at 12:34
And [Run a module in IDLE (Python 3.4) without Restart](https://stackoverflow.com/q/41926321) looks relevant too. — Martijn Pieters, Aug 19 '19 at 12:38
@MartijnPieters It doesn't answer the way I want. I know that I can hit enter on each line but I would not want to hit enter on dozens of line one by one. — Nouman, Aug 19 '19 at 12:40

iko · Answer 1 · 2019-08-10T11:35:31.547

1

I'm not sure if you can make them stay, sorry.

Python restarts when you launch a file in IDLE (it even states RESTART).

Edit: Try defining variables, methods or classes - they too will be gone, not just your imports.

Edit two: You can import your file (python will automaticly execute it), that will not restart python so you will keep what you defined/imported.

edited Aug 10 '19 at 11:35

answered Aug 10 '19 at 11:32

iko

46
5

as he said , you should not restart the file – Rebai Ahmed Aug 10 '19 at 11:34

score 0 · Answer 2 · answered Aug 10 '19 at 11:37

Maybe just to add why this is the case...

Every Python program must have some module that is in "control" of the program. This is the same as in C where you have a "main".

If you want to use functions from file_just_ran.py, then you should define those as functions and then import them into your session. Then the session is in control.

If you want the scrip to be in control, then you must do these import etc either in the script, or in a file that that script can import.

Otherwise, how does the interpreter know what to do? You're trying to execute commands in a running python program?

If you just want to run scripts and code in an interpreter in parallel, then open two sessions.

The imported modules get unimported after running a python file

2 Answers2