Variables in Python are just pointers, as far as I know.
Based on this rule, I can assume that the result for this code snippet:
i = 5
j = i
j = 3
print(i)
would be 3.
But I got an unexpected result for me, and it was 5.
Moreover, my Python book does cover this example:
i = [1,2,3]
j = i
i[0] = 5
print(j)
The result would be [5,2,3].
What am I understanding wrong?
We call them references. They work like this
i = 5 # create int(5) instance, bind it to i
j = i # bind j to the same int as i
j = 3 # create int(3) instance, bind it to j
print i # i still bound to the int(5), j bound to the int(3)
(Sidenote: Small ints are interned, but that isn't important to this explanation)
i = [1,2,3] # create the list instance, and bind it to i
j = i # bind j to the same list as i
i[0] = 5 # change the first item of i
print j # j is still bound to the same list as i