Are Python instance variables thread-safe?

Question

OK, check following codes first:

class DemoClass():

    def __init__(self):
        #### I really want to know if self.Counter is thread-safe. 
        self         


        

Answer 1

self.Counter is an instance variable, so each thread has a copy.

If you declare the variable outside of __init__(), it will be a class variable. All instances of the class will share that instance.