Continue a recursive function in python

Question

I would like to know how to write a function that is repeated without getting the error message :

RecursionError: maximum recursion depth exceeded in instancecheck_

The repeated recursive function is main():

import tkinter as tkin
import math
import hmac
import hashlib
import sys

n = 0
sys.setrecursionlimit(2450)
root= tkin.Tk()
canvas1 = tkin.Canvas(root, width = 300, height = 300)
canvas1.pack()
label1 = tkin.Label(root, text= 'Number', fg='green', font=('helvetica', 12, 'bold'))
canvas1.create_window(150, 200, window=label1)

def dice ( serverSeed, clientSeed, nonce ):
    round = 0
    nonceSeed = '{}:{}:{}'.format(clientSeed, nonce, round)
    hex = hmac.new(bytes(serverSeed, 'utf-8'), bytes(nonceSeed, 'utf-8'), hashlib.sha256).hexdigest()[0:8]
    i = 0
    end = 0
    while i < 4:
        end += int(hex[i*2:i*2+2], 16) / math.pow(256, i+1)
        i+=1
    end = math.floor(end * 10001) / 100
    return str(end)
    
def main ():
    global n
    n += 1
    roll = float(dice('535e8f53eee1402b242c7eff4038787d3de850c3ba27bde6a370225e1a2f23dd', '8cf82c02b3', n))
if n % 2400 == 0:
        label1.configure(text=roll)
        label1.update();
    main()
   
button1 = tkin.Button(text='Click Me',command=main, bg='brown',fg='white')
canvas1.create_window(150, 150, window=button1)

root.mainloop()

Edit: Added limit for recursion and root.after(int, function)

limit = 2400
def main ():
    global n
    global max
    n += 1
    roll = float(dice('535e8f53eee1402b242c7eff4038787d3de850c3ba27bde6a370225e1a2f23dd', '8cf82c02b3', n))
    if n % limit == 0:
        label1.configure(text=roll)
        label1.update();
        limit+=2400
        root.after(0, main)
    else:
        main()

Why do you want an infinite recursion loop? Use a while loop instead. — 12944qwerty, May 20 '21 at 18:15
Does this answer your question? [What is the maximum recursion depth in Python, and how to increase it?](https://stackoverflow.com/questions/3323001/what-is-the-maximum-recursion-depth-in-python-and-how-to-increase-it) — Jonathan Feenstra, May 20 '21 at 18:17
You're making a recursion loop with no exit condition. Move the `main()` inside your main function to an `else` block. — deseuler, May 20 '21 at 18:18
Don't use recursion as a substitute for looping. This isn't Scheme. — Barmar, May 20 '21 at 18:22
@KrisztianNagyZsolt if the maximum is insufficient, recursion is just not a suitable solution. Use a loop instead as other comments have suggested. — Jonathan Feenstra, May 20 '21 at 18:40

score 0 · Answer 1 · answered May 20 '21 at 18:21

Why don't you write something like this

def main ():
    n = 0
    while True:
        n += 1
        roll = dice('535e8f53eee1402b242c7eff4038787d3de850c3ba27bde6a370225e1a2f23dd', '8cf82c02b3', n)
        if n % 2440 == 0:
            label1.configure(text=roll)
            label1.update();

edit - I see people have suggested this while I typed the answer

score 0 · Accepted Answer · answered May 20 '21 at 18:43

Why do you want to go past the maximum recursion? This is not what recursion is for.
While this will not answer your question, as I see no point in increasing recursion depth, I will try to explain a few things.

Recursion is not a substitute for a loop. Yes, it can replace a loop, but it works differently.

Every time you call a function, the data in the function is saved in your memory until that function returns or until that memory is released in a different way (uncaught exception, del or overriding).

Imagine a theoretical function that loads 500MB to the memory, if you call it within itself, you will have 1GB in your memory. Call it again in itself and you will have 1.5GB.
Imagine what happens if you decide to do an infinite recursion. If this recursion reaches a return condition then all that memory will be released, otherwise it will keep on stacking until you run out of memory.

Work with loops, they are better for what you need.

Continue a recursive function in python

2 Answers2