与在每次迭代前检查循环条件不同，而是在迭代结束时检查条件。

Rather than checking the loop condition before each iteration, the condition is checked at the end of the iteration.

youdao

由于在每次迭代之前检查循环条件，因此，如果条件最初为false，则循环中的步骤不运行。

Since the loop condition is checked before each iteration, the steps in the loop would not run at all if the condition is initially false.

youdao

因为没有检查循环数据的起始点，并且不能再次连接到“法兰克福市”，所以将从CONNECT BY子句中删除该中转(Arrival ' Frankfurt ')。

Because the starting point is not checked for cyclic data and 'Frankfurt' must not be connected again, it is eliminated in the connect BY clause (Arrival 'Frankfurt').

youdao

Condition," this thing in the middle between the semicolons, is going to be checked every iteration of the loop.

条件，“这个在两个分号的中间，它将迭代地检查这个循环的条件。

哈佛公开课 - 计算机科学课程节选

It's not a good thing if you're just looping and checking some condition, but never actually changing the state of the world.

这不是一个好事情，如果你只是循环,检查一些条件，但是永远不要改变世界上的国家。

哈佛公开课 - 计算机科学课程节选

And when I'm done with the whole thing, before I end the increment of the variable, you know, when I'm done, I'm just not returning anything out.

在循环外面初始化它，然后做一个终结测试，然后在循环内部有一个指令集，在这个例子中，就是对余数做检查，然后显示信息，当我完成了整个循环。

麻省理工公开课 - 计算机科学及编程导论课程节选