How to stop a "for loop", and continue running the code later after manually inputting a command?

Question

I have a file that looks like this called myLoop.py

for i in range(100):
     print(i)

I run the file like so: python3 myLoop.py

I want to stop the code after reaching i = 10

Then, I want to manually start the code again by typing python3 myLoop.py or whatever necessary into the terminal, to have the code pick up after i = 10.

Then, I want the code to then stop at i = 30, then continue via a manual command again until the code completes at i = 99.

To be clear, I want to manually send a statement to the terminal in order to have the code pick up where it left off.

I want to use the pickle module to accomplish this, here are some links I've looked through related to it:

https://docs.python.org/3/library/pickle.html

https://www.geeksforgeeks.org/understanding-python-pickling-example/

https://realpython.com/python-pickle-module/

How to stop a for loop while in execution

This post is said to be a duplicate of the following posts, but neither provide any examples of the use of the pickle module for this purpose. The first post simply has an embedded link of the first URL I've read, and the other provides an example of JSON's use case. This post is not a duplicate of either.

Saving the state of a program to allow it to be resumed

Best method of saving data

Use the pickle module to save the value of i to a file after each iteration of the loop. Then, when you want to start the code again, you can read the value of i from the file and use it to continue the loop. — Saggy, Dec 28 '22 at 20:32
_I want to stop the code after reaching `i = 10`_ Do you mean you want the python program to completely exit? Or do you just want it to pause? — John Gordon, Dec 28 '22 at 20:34
The code would stop after reaching ```i = 10``` and again at ```i = 30```. — FrustratedSnake, Dec 28 '22 at 21:21

Ferhat Mousavi · Answer 1 · 2022-12-28T20:43:27.203

0

Maybe this can help you

start = 0
try:
    with open("state.txt", "rt") as fp:
        state = fp.read()

    if int(state) > 0:
        start = int(state) + 1
except:
    pass
for i in range(start, 100):

    print(i)
    if i == 10 or i == 30:
        with open("state.txt", "wt") as fp:
            fp.write(f"{i}")
            break

edited Dec 28 '22 at 20:43

answered Dec 28 '22 at 20:41

Ferhat Mousavi

124
8

This does not use the pickle module, nor does it completely exit. – FrustratedSnake Dec 28 '22 at 21:12
You can use `pickle` by yourself. You can use `exit()` instead of `break` if this is part of your program. – Ferhat Mousavi Dec 28 '22 at 21:21
Yes, the purpose of the question is to understand how to do this. Like I stated in the post, I have read the documentation of pickle, but do not understand how to implement it. – FrustratedSnake Dec 28 '22 at 21:38
first import pickle and then just change `"wt"` to `"wb"` and `"rt"` to `"rb"` and also instead of `fp.read()` write `pickle.load(fp)` and instead of `fp.write(f"{i}")` write `pickle.dump(i, fp)`. and at the end change break to `exit()`. – Ferhat Mousavi Dec 28 '22 at 22:42
I'm confused as to how to continue the program from the stopping point. Do I enter ```python3 myLoop.py``` into the terminal? – FrustratedSnake Dec 28 '22 at 22:49
yes as you mentioned above – Ferhat Mousavi Dec 28 '22 at 22:50

How to stop a "for loop", and continue running the code later after manually inputting a command?

1 Answers1