首先我们将构建该筛选器的右侧部分，从运算符is开始。

First we'll build the right part of the filter, starting from operator Is.

youdao

开始时使用to运算符。

To start, use the to operator.

youdao

其中一个技巧是子表达式开始处的？：运算符。

One such trick is the? : operator at the beginning of a subexpression.

youdao

I can write it explicitly. I can write it inside of a FOR loop. And we've started to add, and we'll see a lot more of this, examples of collections of structures so that we don't just have to do something that can be easily described as walking through a set of things but can actually be a collection that you walk through.

我可以明确的写出来,我可以把它在FOR循环的内部写出来，然后我们开始学习了add这个运算符,我们会在以后学习很多的,集合的数据结构的例子,这样一来我们可以进行一些,很简单的遍历集合的操作,我想要为大家指出的最后一件事情是。

麻省理工公开课 - 计算机科学及编程导论课程节选