Declare your collection variable to be of that type, and be sure to create an object of that same type.

将您的集合变量声明为该类型，并确保创建一个相同类型的对象。

youdao

This variable should be typed so that it's compatible with each item in the list, array, or collection being iterated over.

这个变量应该有自己的类型，这样，它就可以与将遍历的列表、数组或集合中的每一个项兼容。

youdao

Any subsequent request for this context variable returns the collection of courses already prepared.

任何针对此上下文变量的后续请求都会返回已经准备好的课程集合。

youdao

And what it's saying semantically is, using that variable as my placeholder, have it walk through this collection, starting at the first thing, execute that code, then the next thing, execute that code, and so on.

它的语义意思就是，把这个变量应用为我的占位符，用它来遍历这个集合，从第一个元素开始，执行代码，然后下一个元素，再执行代码。

麻省理工公开课 - 计算机科学及编程导论课程节选

However, the quality of the collection has been variable.

BBC: Museum of Somerset marine insect fossil study starts