Question

I want to build a hash from an array of rows from a DB. I can easily do it with the code below. I’ve come to Ruby from PHP and this is how I would do it. Is there a better/proper way to do this in Ruby (or Rails)?

def features_hash
  features_hash = {}
  product_features.each do |feature|
    features_hash[feature.feature_id] = feature.value
  end

  features_hash
end

# {1 => 'Blue', 2 => 'Medium', 3 => 'Metal'}

Answer 1

You can use Hash[]:

Hash[ product_features.map{|f| [f.feature_id, f.value]}  ]

Would you like this better?

product_features.map{|f| [f.feature_id, f.value]}.to_h # no available (yet?)

Then go and check out this feature request and comment on it!

Alternative solutions:

product_features.each_with_object({}){|f, h| h[f.feature_id] = f.value}

There is also group_by and index_by which could be helpful, but the values will be the features themselves, not their value.