for

The for loop iterates over ranges of values or the items in a collection:

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Speaker Notes
  • Under the hood for loops use a concept called “iterators” to handle iterating over different kinds of ranges/collections. Iterators will be discussed in more detail later.
  • 请注意，for 循环只迭代到 4。现在展示使用 1..=5 语法表示一个包含边界的范围。