Ruby:从 Ruby 中的变量创建哈希键和值 [英] Ruby: Creating a hash key and value from a variable in Ruby

问题描述

我有一个变量 id，我想将它用作散列中的键，以便分配给该变量的值用作散列的键.

I have a variable id and I want to use it as a key in a hash so that the value assigned to the variable is used as key of the hash.

例如，如果我有变量 id = 1 所需的结果散列将是 { 1: 'foo' }.

For instance, if I have the variable id = 1 the desired resulting hash would be { 1: 'foo' }.

我试过用，

{
  id: 'foo'
}

但这不起作用，而是产生了一个带有符号 :id 到 'foo' 的散列.

But that doesn't work, instead resulting in a hash with the symbol :id to 'foo'.

我可以发誓我以前做过这件事，但我完全是在画一个空白.

I could have sworn I've done this before but I am completely drawing a blank.

推荐答案

如果你想用某些值填充新的哈希值，你可以将它们传递给 Hash::[]:

If you want to populate a new hash with certain values, you can pass them to Hash::[]:

Hash["a", 100, "b", 200]             #=> {"a"=>100, "b"=>200}
Hash[ [ ["a", 100], ["b", 200] ] ]   #=> {"a"=>100, "b"=>200}
Hash["a" => 100, "b" => 200]         #=> {"a"=>100, "b"=>200}

所以在你的情况下:

Hash[id, 'foo']
Hash[[[id, 'foo']]]
Hash[id => 'foo']

最后一个语法 id =>'foo' 也可以与 {} 一起使用:

The last syntax id => 'foo' can also be used with {}:

{ id => 'foo' }

否则，如果哈希已经存在，请使用 Hash#=[]:

Otherwise, if the hash already exists, use Hash#=[]:

h = {}
h[id] = 'foo'

这篇关于Ruby:从 Ruby 中的变量创建哈希键和值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！