But when you start writing programs, especially when we get to web-based stuff where you want -- to check the user's input -- is it valid, is it an email address, -- and all these different scenarios -- it's actually often useful to be able to just enumerate them or rattle them off using this switching construct instead.

但是当你看是写程序时，特别是当我们,使用基于网络的东西，你想要,检查用户的输入-,它是合法的吗？它是不是一个电子邮箱地址？,所有的这些场景-,实际上它常常是有用的，当你用枚举结构列举它们,或者用它来快速地来说出它们。

哈佛公开课 - 计算机科学课程节选

This thing's nice because rather than do "if" and "and and" or "or or" and all of this, you can instead enumerate things a little more cleanly, albeit apparently at the expense of more white space.

这个东西是不错的，因为它不用“if“和“and，and“,或者“or，or“所有的这些，你可以用枚举来更清楚地表达它，虽然表面上它用了更多的空格。

哈佛公开课 - 计算机科学课程节选