这在 Ruby 语言中是什么意思? [英] What does this mean in Ruby language?

问题描述

运行以下代码，

a = [1, 2, 3, 4, 5]
head, *tail = a
p head
p tail

你会得到结果

1
[2, 3, 4, 5]

谁能帮我解释下语句head,*tail = a，谢谢！

Who can help me to explain the statement head,*tail = a, Thanks!

推荐答案

head, *tail = a 表示将数组的第一个元素 a 赋值给 head，并将其余元素分配给 tail.

head, *tail = a means to assign the first element of the array a to head, and assign the rest of the elements to tail.

*，有时被称为splat 操作符"，对数组做了很多事情.当它位于赋值运算符 (=) 的左侧时，如您的示例所示，它仅表示保留所有剩余内容."

*, sometimes called the "splat operator," does a number of things with arrays. When it's on the left side of an assignment operator (=), as in your example, it just means "take everything left over."

如果您在该代码中省略了 splat，它将改为这样做:

If you omitted the splat in that code, it would do this instead:

head, tail = [1, 2, 3, 4, 5]
p head # => 1
p tail # => 2

但是当您将 splat 添加到 tail 时，它意味着所有没有分配给前面的变量 (head)，分配给 tail."

But when you add the splat to tail it means "Everything that didn't get assigned to the previous variables (head), assign to tail."

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