实际上，为序列编制索引可能是最常用的序列操作——究竟为什么在迭代器上无法使用索引呢？

In fact, indexing into a sequence is probably the most common thing you ever do with a sequence — why on earth does it fall down so badly on iterators? For example.

youdao

例如，当您使用我们的搜索引擎的时候，我们会记录哪些是最常用的搜索词汇。

For example, when you use our search engine, we may keep track of which search terms are popular.

youdao

制作抽认卡最常用的方法是使用索引卡。

The most common way to create flashcards is to use index CARDS.

youdao