第309页 | Learning Python | 阅读 ‧ 电子书库

break, continue, pass, and the Loop else

Now that we’ve seen a few Python loops in action, it’s time to take a look at two simple statements that have a purpose only when nested inside loops—the break and continue statements. While we’re looking at oddballs, we will also study the loop else clause here, because it is intertwined with break, and Python’s empty placeholder statement, the pass (which is not tied to loops per se, but falls into the general category of simple one-word statements). In Python:

break

Jumps out of the closest enclosing loop (past the entire loop statement)

continue

Jumps to the top of the closest enclosing loop (to the loop’s header line)

pass

Does nothing at all: it’s an empty statement placeholder

Loop else block

Runs if and only if the loop is exited normally (i.e., without hitting a break)