我如何比较两个哈希值？ [英] How do I compare two hashes?

问题描述

 ＃！/ usr / bin / env ruby​​ $ 
使用下面的代码来比较两个Ruby Hashes： b 
 $ b需要yaml
需要active_support
 
 file1 = YAML :: load（File.open（'./ en_20110207.yml'））
 file2 = YAML :: load（File.open（'./ locales / en.yml'））
 
 arr = [] 
 
 file1.select {| k， v | 
 file2.select {| k2，v2 | 
 arr<< ＃{v2}如果＃{v}！=＃{v2}
} 
} 
 
放置
  

屏幕的输出是来自file2的完整文件。我知道一个事实，即文件是不同的，但脚本似乎没有把它拿起来。 你可以直接比较哈希值是否相等：

  hash1 = {'a'=> 1，'b'=> 2} 
 hash2 = {'a'=> 1，'b'=> 2} 
 hash3 = {'a'=> 1，'b'=> 2，'c'=> 3} 
 
 hash1 == hash2＃=> true 
 hash1 == hash3＃=> false 
 
 hash1.to_a == hash2.to_a＃=> true 
 hash1.to_a == hash3.to_a＃=>假
  

---

---

<您可以将散列转换为数组，然后获得它们的区别：

  hash3.to_a  -  hash1.to_a＃=> [[c，3]] 
 
 if（hash3.size> hash1.size）
 difference = hash3.to_a  -  hash1.to_a 
 else 
 difference = hash1.to_a  -  hash3.to_a 
 end 
 Hash [* difference.flatten]＃=> {c=> 3} 
  

---

简化进一步：

通过三元结构分配差异：

 差值= （hash3.size> hash1.size）\ 
？ hash3.to_a  -  hash1.to_a \ 
：hash1.to_a  -  hash3.to_a 
 => [[c，3]] 
散列[* difference.flatten] 
 => {c=> 3} 
  

在一个操作中完成所有操作， code $>变量：

  Hash [*（
（hash3。 hash1.to_a  -  hash3.to_a 
）.flatten] 
 => ;. {c=> 3} 
  

I am trying to compare two Ruby Hashes using the following code:

#!/usr/bin/env ruby

require "yaml"
require "active_support"

file1 = YAML::load(File.open('./en_20110207.yml'))
file2 = YAML::load(File.open('./locales/en.yml'))

arr = []

file1.select { |k,v|
  file2.select { |k2, v2|
    arr << "#{v2}" if "#{v}" != "#{v2}"
  }
}

puts arr

The output to the screen is the full file from file2. I know for a fact that the files are different, but the script doesn't seem to pick it up.

解决方案

You can compare hashes directly for equality:

hash1 = {'a' => 1, 'b' => 2}
hash2 = {'a' => 1, 'b' => 2}
hash3 = {'a' => 1, 'b' => 2, 'c' => 3}

hash1 == hash2 # => true
hash1 == hash3 # => false

hash1.to_a == hash2.to_a # => true
hash1.to_a == hash3.to_a # => false

---

---

You can convert the hashes to arrays, then get their difference:

hash3.to_a - hash1.to_a # => [["c", 3]]

if (hash3.size > hash1.size)
  difference = hash3.to_a - hash1.to_a
else
  difference = hash1.to_a - hash3.to_a
end
Hash[*difference.flatten] # => {"c"=>3}

---

Simplifying further:

Assigning difference via a ternary structure:

  difference = (hash3.size > hash1.size) \
                ? hash3.to_a - hash1.to_a \
                : hash1.to_a - hash3.to_a
=> [["c", 3]]
  Hash[*difference.flatten] 
=> {"c"=>3}

Doing it all in one operation and getting rid of the difference variable:

  Hash[*(
  (hash3.size > hash1.size)    \
      ? hash3.to_a - hash1.to_a \
      : hash1.to_a - hash3.to_a
  ).flatten] 
=> {"c"=>3}

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