如何测试散列顺序意识的平等 [英] How to test order-conscious equality of hashes

问题描述

Ruby 1.9.2将订单引入哈希。鉴于订单，我如何测试两个哈希值是否相等？

鉴于：

  h1 = {a=> 1，b=> 2，c=> 3} 
 h2 = {a=> 1，c=> ; 3，b=> 2} 
  

我想要一个返回 false 为 h1 和 h2 。以下任何一项都无效：

  h1 == h2＃=>真
 h1.eql？ h2＃=> true 
  

解决方案

您可以比较 方法：

  h1 = {one：1，two：2，three： 3}＃=> {：one => 1，：two => 2，：three => 3} 
 h2 = {three：3，one：1，two：2}＃=> {：three => 3，：one => 1，：two => 2} 
 h1 == h2＃=> true 
 h1.keys＃=> [：one，：two，：three] 
 h2.keys＃=> [：three，：one，：two] 
 h1.keys.sort == h2.keys.sort＃=> true 
 h1.keys == h2.keys＃=>假
  

但是，根据密钥插入顺序比较Hashes有点奇怪。取决于你想要做什么，你可能想重新考虑你的基础数据结构。

Ruby 1.9.2 introduced order into hashes. How can I test two hashes for equality considering the order?

Given:

h1 = {"a"=>1, "b"=>2, "c"=>3}
h2 = {"a"=>1, "c"=>3, "b"=>2}

I want a comparison operator that returns false for h1 and h2. Neither of the followings work:

h1 == h2 # => true
h1.eql? h2 # => true

解决方案

You could compare the output of their keys methods:

h1 = {one: 1, two: 2, three: 3} # => {:one=>1, :two=>2, :three=>3}
h2 = {three: 3, one: 1, two: 2} # => {:three=>3, :one=>1, :two=>2}
h1 == h2 # => true
h1.keys # => [:one, :two, :three]
h2.keys # => [:three, :one, :two]
h1.keys.sort == h2.keys.sort # => true
h1.keys == h2.keys # => false

But, comparing Hashes based on key insertion order is kind of strange. Depending on what exactly you're trying to do, you may want to reconsider your underlying data structure.

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