Can you explain the output of this code,please?

Question

a=[0,1,2,3]
For a[-1] in a:
print(a[-1])

Output is 0 1 2 2

Answer 1

In a regular for loop, when you write for x in whatever, x will take the value of each element.

That's like writing:

x = whatever[0]
do stuff
x = whatever[1]
do stuff and so on.

So here, you're assigning a new value to a[-1] with every iteration.

So when you finally reach a[-1], you access 2, which is still stored there from the round before.

Answer 2

a [-1] is the last element of the array
and in the loop it takes values ​​of the array itself:
a = [ 0,1,2, 0 ]
a = [ 0,1,2, 1 ]
a = [ 0,1,2, 2 ]
a = [ 0,1,2, 2 ]