在Ruby中从变量创建一个散列键？ [英] Creating a hash key from a variable in Ruby?

问题描述

我有一个变量 id ，我想用它作为哈希键，这样分配给变量的值就可以用作哈希键。 / p>

例如，如果我有变量 id = 1 ，则所需的结果散列值将为 {1：'foo'} 。

我已经尝试创建哈希，

  {
 id：'foo'
} 
  

但这不起作用，取而代之的是使用符号：id 到'foo'。

我可以发誓我之前完成了这个工作，但我完全画空白。

解决方案

如果你想用特定值填充一个新的散列，你可以将它们传递给 Hash :: [] ：

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

：

  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：

  {id => 'foo'} 
  

否则，如果散列已经存在，请使用 Hash＃= []


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




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.

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

I've tried creating the hash with,

{
  id: 'foo'
}

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

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

解决方案

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}

So in your case:

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

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

{ id => 'foo' }

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

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

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