How to join thread from another function

I have some code like:

import threading
import time

mode1=False
mode2=True

stop_thread=False

def function1():
     while True:
        print('function1')
        
        global stop_thread
        if stop_thread:
            break
def function2():
    while True:
        print('function2')
        
        global stop_thread
        if stop_thread:
            break

class MyClass():
    def run(self):
        if mode1:
            t = threading.Thread(target=function1, daemon=True)
            t.start()
        elif mode2:
            t = threading.Thread(target=function2, daemon=True)
            t.start()

    def stop(self):
        global stop_thread
        stop_thread=True
        # t.join() doesn't work here

        
v=MyClass()
v.run()
v.stop()

How can I make it possible to join() the thread from stop()?

You just need to save the reference to the thread as an attribute of the MyClass instance:

import threading
import time

mode1 = False

stop_thread = False

def function1():
     while True:
        print('function1')

        if stop_thread:
            break

def function2():
    while True:
        print('function2')

        if stop_thread:
            break

# t=None
class MyClass():
    def run(self):
        fn = function1 if mode1 else function2
        # Save reference to the thread as an attribute of this instance:
        self.t = threading.Thread(target=fn, daemon=True)
        self.t.start()

    def stop(self):
        global stop_thread #,t

        stop_thread = True
        self.t.join()
        print('thread has been joined')


v = MyClass()
v.run()
v.stop()

Prints:

function2
thread has been joined