I want to make the list not affect each other.

Both ex and EX are caused by pointing to the same list object.
You can clone a list element to create a new list object.

We usually use two methods.

copyHow to use the method

EX = ex.copy()

How to use slicing

EX = ex[:]

If the list contains objects of different mutable types, you may need deepcopy.
deepcopy recursively copies all elements within the list.

import copy

a = [[1, 2], [3, 4]]
b = a.copy()
c = copy.deepcopy(a)

a[0][0] = 0

print(a)  # [[0, 2], [3, 4]]
print(b)  # [[0, 2], [3, 4]]
print(c)  # [[1, 2], [3, 4]]