Question

I am using Ruby on Rails 3.2.2 and Ruby 1.9.3. I would like to compare two Hashes (A and B) so to return true if a Hash (A) include all keys/values of the other Hash (B).

For example, given I have

params.inspect
# => { "action"=>"...", "controller"=>"...", "key_param1"=>"value_param1", , "key_param2"=>"value_param2", "key_param3"=>"value_param3", ... }

my_hash1.inspect
# => { "key_param1"=>"value_param1", "key_param2"=>"value_param2" }

my_hash2.inspect
# => { "key_param4"=>"value_param4", "key_param1"=>"value_param1" }

my_hash3.inspect
# => {}

Then I am looking for a method (or something like that) in order to make

params.has_same_keys_and_values_as?(my_hash1)
# => true

params.has_same_keys_and_values_as?(my_hash2)
# => false

params.has_same_keys_and_values_as?(my_hash3)
# => true

Answer 1

class Hash
  def >=(b)  
    eq = true
    b.each { |k, v| eq &= !(self.include? k) ? false : ( ( ((self[k]&&v).is_a? Hash) && !((v||self[k]).empty?) ) ? self[k]>=v : true)}

    return eq
  end

end
params = { "action"=>"...", "controller"=>"...", "key_param1"=>"value_param1", "key_param2"=>"value_param2", "key_param3"=>"value_param3" }
my_hash1 = { "key_param1"=>"value_param1", "key_param2"=>"value_param2" }
my_hash2 = { "key_param4"=>"value_param4", "key_param1"=>"value_param1" }
my_hash3 = {}

p params >= my_hash1 #true
p params >= my_hash2 #false
p params >= my_hash3 #true

It’ll work with “deep” hashes as well:

b = {1 => {2 => {} }, 4 => {} }
a = {1 => {2 => {3 => {} }}, 4 => {}, 5 => "123" }

p a >= b #true
p b >= a #false

P.S.

Whether one hash includes another hash