While-else and for-else: when the else clause runs and when break skips it

Python lets a loop have an else clause, which surprises people who know else only from if. The else block is written at the same indentation as the for or while header and runs once, after the loop, if the loop finished normally. "Normally" means the while condition became false or the for loop ran out of items. If the loop was ended by break, the else block is skipped.