Why A[0,0,3,0,1]

Question

A=[1,2,3,4,1]
for n in A:
A[n]=0
print(A)

Answer 1

Alexander Kucherov
array changes after each iteration and therefore value of variable n changes. So the value of n will be changing according to the elements present at array.
So n = [1, 2, 3, 4, 1]
A = [1, 2, 3, 4, 1]
When n=1:-
A[1] = 0
So now array index 1 become 0 so array A= [1, 0, 3, 4, 1]
n =1 is accessed so now next index and element which n=0 so it will be used for array iteration n=0
A[0] = 0
So A = [0, 0, 3, 4, 1]
Now the next array element and index is 2 so n = 3 is in iteration
A[3] = 0
So array element 4th change to 0
So now A = [0, 0, 3, 0, 1]
Now next iteration for index 3 is 0 so value of n = 0 so again 0th index value in array A will set to 0
A[0] = 0
So array A will become
A = [0, 0, 3, 0, 1]
Now only index 4th and last element is need to be traversed which is n = 1 so now again A[1] will set to 0 which is also already set so
A[1] = 0
So A = [0, 0, 3, 0, 1] so in this way after traversing the whole array the output become
A = [0, 0, 3, 0, 1]

Answer 2

Here is two more threads where answer are explained in different ways so go an have an read
https://www.sololearn.com/Discuss/2020974/?ref=app
https://www.sololearn.com/Discuss/1354820/?ref=app