Can someone explain why value of x and y not same?

Question

# Python code
a = [1,2,3,4,1]
for x in a:
print(x)
print("\n")
for y in a:
print(y)
a[y] = 0

# output
1 2 3 4 1
1 0 3 0 1

Answer 1

For x you can directly understand that, there it iterates over list and prints element

now for y you are replacing element after printing.
First a[1] = 0(as y is 1 for the first iteration) this changes index one element to 0 so you can understand for every element

Answer 2

You tagged three languages: python, c++, java. Only one is relevant.

Answer 3

The reason why the output is different is that you change a inside the second loop.

Answer 4

Get rid of the irrelevant tags.

Answer 5

Simon Sauter which tag? Code is running without error.

Answer 6

Got the answer. Changing the list inside loop and iterating over same list. Due to which list next index data of the iterating list is getting modified.