python_notes.md

Notes from SO

Looping

1. If you're talking about starting over from the beginning of the for loop, there's no way to do that except "manually", for example by wrapping it in a while loop:

should_restart = True
while should_restart:
  should_restart = False
  for i in range(10):
    print i
    if i == 5:
      should_restart = True
      break

This restarts the loop over and over - anytime it reaches 5, it started over - leads to infinite loop.

2. How does a while loop actually stop?

A while loop doesn't automatically exit in mid-loop as soon as its condition is no longer true; it just checks the condition at the start of each loop. If you want to get out early, you need to break explicitly (or do something else non-local, like return from the function or raise to an except handler outside the loop).