Check if a hash's keys include all of a set of keys

user_359890 0
Viewed 35537

I'm looking for a better way to do

if hash.key? :a &&
   hash.key? :b &&
   hash.key? :c &&
   hash.key? :d

preferably something like

hash.includes_keys? [ :a, :b, :c, :d ]

I came up with 

hash.keys & [:a, :b, :c, :d] == [:a, :b, :c, :d]

but I dont like having to add the array twice though

ruby
6 Answers

Here is my solution:

(also given as answer at)

class Hash
    # doesn't check recursively
    def same_keys?(compare)
      return unless compare.class == Hash
        
      self.size == compare.size && self.keys.all? { |s| compare.key?(s) }
    end
end

a = c = {  a: nil,    b: "whatever1",  c: 1.14,     d: false  }
b     = {  a: "foo",  b: "whatever2",  c: 2.14,   "d": false  }
d     = {  a: "bar",  b: "whatever3",  c: 3.14,               }

puts a.same_keys?(b)                    # => true
puts a.same_keys?(c)                    # => true
puts a.same_keys?(d)                    # => false   
puts a.same_keys?(false).inspect        # => nil
puts a.same_keys?("jack").inspect       # => nil
puts a.same_keys?({}).inspect           # => false
user_61104510
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