Why this output?

Question

I can't understand why this result.
https://code.sololearn.com/cQhUHQIMBnZb/?ref=app

Answer 1

"for i in list" means assigning "i" to every element in a list on each loop. Therefore "for a[-1] in a" means assigning "a[-1] = a[element]".

In your code the list changes at every loop:
1st loop: [0,1,2,3,0]
2nd [0 1 2 3 1]
3rd [0 1 2 3 2]
4th [ 0 1 2 3 3]
5th [0 1 2 3 3]

So at final loop "a[-1]" is 3

Answer 2

the a[-1] in the for loop becomes your variable for holding values in a