How do i pass by reference?

Question

def func(x,y):
x = y

x = 10
print(x)
func(x,20)
print(x)

Outputs =
10
10

How do i make it so that value of x is changed to 20?

Answer 1

You cannot pass integer values as references, it is not like in C or C++. The difference is that in Python either the type of variable is a reference by itself or you simply pass the value.

For instance, if you pass an object like a list, you can change what's inside it.

Thus, the only way I see for you is, for example, to create a list with the x value inside, and then pass it. The value inside the list will change.

def func(x: list, y):
if len(x) > 0:
x[0] = y

x = [10]
print(x[0]) # it prints 10
func(x, 20)
print(x[0]) # it prints 20

Hope that helps!

Answer 2

Here is a very good part of a python tutorial. It's not up to date regarding the python version (print is without ()), but anyway it gives a good view on how parameters and arguments work in python. Also other parts of the tutorial are worth taking a look at.
https://www.python-course.eu/passing_arguments.php

Answer 3

thx