두 해시를 어떻게 비교합니까?

두 해시를 어떻게 비교합니까?

---

다음 코드를 사용하여 두 개의 Ruby Hashe를 비교하려고합니다.

#!/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

화면 출력은 file2의 전체 파일입니다. 나는 파일이 다르다는 사실을 알고 있지만 스크립트가 그것을 선택하지 않는 것 같습니다.

---

해시를 직접 비교할 수 있습니다.

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

---

---

해시를 배열로 변환 한 다음 그 차이를 얻을 수 있습니다.

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}

---

추가 단순화 :

삼항 구조를 통해 차이 할당 :

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

한 번의 작업으로 모든 작업을 수행하고 difference변수를 제거 합니다.

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

---

해시의 해시와 배열을 자세히 비교할 수 있는 hashdiff gem을 사용해 볼 수 있습니다 .

다음은 그 예입니다.

a = {a:{x:2, y:3, z:4}, b:{x:3, z:45}}
b = {a:{y:3}, b:{y:3, z:30}}

diff = HashDiff.diff(a, b)
diff.should == [['-', 'a.x', 2], ['-', 'a.z', 4], ['-', 'b.x', 3], ['~', 'b.z', 45, 30], ['+', 'b.y', 3]]

---

두 해시의 차이점을 얻으려면 다음을 수행하십시오.

h1 = {:a => 20, :b => 10, :c => 44}
h2 = {:a => 2, :b => 10, :c => "44"}
result = {}
h1.each {|k, v| result[k] = h2[k] if h2[k] != v }
p result #=> {:a => 2, :c => "44"}

---

Rails는 이 메소드를 더 이상 사용하지 않습니다diff .

빠른 한 줄짜리 :

hash1.to_s == hash2.to_s

---

You could use a simple array intersection, this way you can know what differs in each hash.

    hash1 = { a: 1 , b: 2 }
    hash2 = { a: 2 , b: 2 }

    overlapping_elements = hash1.to_a & hash2.to_a

    exclusive_elements_from_hash1 = hash1.to_a - overlapping_elements
    exclusive_elements_from_hash2 = hash2.to_a - overlapping_elements

---

I had the same problem and sent a pull request to rails

• Works with deeply nested hash
• Works with arrays of hashes

https://github.com/elfassy/rails/commit/5f3410e04fe8c4d4745397db866c9633b80ccec6

---

If you need a quick and dirty diff between hashes which correctly supports nil in values you can use something like

def diff(one, other)
  (one.keys + other.keys).uniq.inject({}) do |memo, key|
    unless one.key?(key) && other.key?(key) && one[key] == other[key]
      memo[key] = [one.key?(key) ? one[key] : :_no_key, other.key?(key) ? other[key] : :_no_key]
    end
    memo
  end
end

---

If you want a nicely formatted diff, you can do this:

# Gemfile
gem 'awesome_print' # or gem install awesome_print

And in your code:

require 'ap'

def my_diff(a, b)
  as = a.ai(plain: true).split("\n").map(&:strip)
  bs = b.ai(plain: true).split("\n").map(&:strip)
  ((as - bs) + (bs - as)).join("\n")
end

puts my_diff({foo: :bar, nested: {val1: 1, val2: 2}, end: :v},
             {foo: :bar, n2: {nested: {val1: 1, val2: 3}}, end: :v})

The idea is to use awesome print to format, and diff the output. The diff won't be exact, but it is useful for debugging purposes.

---

... and now in module form to be applied to a variety of collection classes (Hash among them). It's not a deep inspection, but it's simple.

# Enable "diffing" and two-way transformations between collection objects
module Diffable
  # Calculates the changes required to transform self to the given collection.
  # @param b [Enumerable] The other collection object
  # @return [Array] The Diff: A two-element change set representing items to exclude and items to include
  def diff( b )
    a, b = to_a, b.to_a
    [a - b, b - a]
  end

  # Consume return value of Diffable#diff to produce a collection equal to the one used to produce the given diff.
  # @param to_drop [Enumerable] items to exclude from the target collection
  # @param to_add  [Enumerable] items to include in the target collection
  # @return [Array] New transformed collection equal to the one used to create the given change set
  def apply_diff( to_drop, to_add )
    to_a - to_drop + to_add
  end
end

if __FILE__ == $0
  # Demo: Hashes with overlapping keys and somewhat random values.
  Hash.send :include, Diffable
  rng = Random.new
  a = (:a..:q).to_a.reduce(Hash[]){|h,k| h.merge! Hash[k, rng.rand(2)] }
  b = (:i..:z).to_a.reduce(Hash[]){|h,k| h.merge! Hash[k, rng.rand(2)] }
  raise unless a == Hash[ b.apply_diff(*b.diff(a)) ] # change b to a
  raise unless b == Hash[ a.apply_diff(*a.diff(b)) ] # change a to b
  raise unless a == Hash[ a.apply_diff(*a.diff(a)) ] # change a to a
  raise unless b == Hash[ b.apply_diff(*b.diff(b)) ] # change b to b
end

---

This was answered in "Comparing ruby hashes". Rails adds a diff method to hashes. It works well.

---

what about convert both hash to_json and compare as string? but keeping in mind that

require "json"
h1 = {a: 20}
h2 = {a: "20"}

h1.to_json==h1.to_json
=> true
h1.to_json==h2.to_json
=> false

---

I developed this to compare if two hashes are equal

def hash_equal?(hash1, hash2)
  array1 = hash1.to_a
  array2 = hash2.to_a
  (array1 - array2 | array2 - array1) == []
end

The usage:

> hash_equal?({a: 4}, {a: 4})
=> true
> hash_equal?({a: 4}, {b: 4})
=> false

> hash_equal?({a: {b: 3}}, {a: {b: 3}})
=> true
> hash_equal?({a: {b: 3}}, {a: {b: 4}})
=> false

> hash_equal?({a: {b: {c: {d: {e: {f: {g: {marino: 1}}}}}}}}, {a: {b: {c: {d: {e: {f: {g: {h: 1}}}}}}}})
=> true
> hash_equal?({a: {b: {c: {d: {e: {f: {g: {marino: 1}}}}}}}}, {a: {b: {c: {d: {e: {f: {g: {h: 2}}}}}}}})
=> false

---

How about another, simpler approach:

require 'fileutils'
FileUtils.cmp(file1, file2)

참고URL : https://stackoverflow.com/questions/4928789/how-do-i-compare-two-hashes