Why doesn't this loop break?

Question

Python noob; please explain why this loop doesn\'t exit.

for i in range(0,10):
  print \"Hello, World!\"
  if i == 5: i = 15
  print i
next

Answer 1

Because for i in whatever means that for each element in whatever, the loop body will be executed once setting i to that element. There is no rule that says that at the end of each iteration, i must still be an element of whatever.

Reassigning i in the loop body has no effect whatsoever on how often the loop body executes or which value i will hold in the next iteration.