为什么我要打印两次对象? [英] Why am I getting objects printed twice?

问题描述

当我在 irb 或 rails 中并使用 each 创建一些迭代时，我会在终端或浏览器中再次打印整个结构.示例:

When I am in irb or in rails and I create some iteration with each, I am getting the whole struct printed again in my terminal or inside the browser. Example:

a = [1,2,3,4]

a.each do |number|
  puts n
end

在irb终端或浏览器内的结果:

The result in irb terminal or inside the browser:

1
2
3
4

=> [1,2,3,4]

为什么这个=>[1,2,3,4] 出现在浏览器里面?我无法在我的页面中创建单个列表，因为整个结构都出现了.

Why does this => [1,2,3,4] appear inside the browser? I can't create a single list in my page because the whole structure appears.

推荐答案

Ruby 中的每个表达式都返回一个值；在irb中，你刚刚执行的表达式返回的值显示在=>之后.

Every expression in Ruby returns a value; in irb, the value returned by the expression you've just executed is displayed after =>.

Enumerable::each 的返回值是调用 each 的对象——在本例中，数组 [1,2,3,4]

The return value of Enumerable::each is the object that called each - in this case, the array [1,2,3,4]

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