Odtnhj

Is there a more elegant way to write this code?

 def create_a_hash_from_a_collection
 my_hash = 

 collection_of_hashes.each do |key, value|
 my_hash[key] = if my_hash[key].nil?
 my_hash[key] = value
 end

 my_hash
 end

The line that seems clumsy to me is this:

my_hash[key] = if my_hash[key].nil?

Is there a shorthand way of expressing it?

You can use ||= operator which does exactly what you want

my_hash[key] ||= 

The rest of my answer here is because I'm not sure what a "collection of hashes" is, so my best guess is that it would be an array of hashes. If I'm wrong, let me know and disregard the rest of this answer.

It seems that the rest of your method may not do what it sounds like you're trying to do. Consider:

@collection_of_hashes = [foo: 'bar', baz: 'qux']

def create_a_hash_from_a_collection
 my_hash = 
 @collection_of_hashes.each do |key, value|
 # this is not actually doing anything here and returns same with or
 # without the following line
 # my_hash[key] ||= 
 my_hash[key] = value
 end

 my_hash
 end
#=> :foo=>"bar"=>nil, :baz=>"qux"=>nil

But what you probably want is

def create_a_hash_from_a_collection
 my_hash = 
 @collection_of_hashes.each do |hash|
 hash.keys.each do |k|
 my_hash[k] = hash[k]
 end
 end
 my_hash
end
#=> :foo=>"bar", :baz=>"qux"

But also keep in mind, if any of your "collection of hashes" which we would tend to assume would be an array of hashes, contain the same key, which one wins? This code, it would be the last item in the array's key value. What is the actual goal of your method?

If you want to have a brand new hash for each key in your initial hash you need to initialise it with a block:

hash = Hash.new hash[key] = 

hash[:foo].object_id == hash[:bar].object_id #=> false

Otherwise, if you do this, It will be always the same default hash

hash = Hash.new()
hash[:foo].object_id == hash[:bar].object_id #=> true

I guess what you want is to initialise your my_hash with a default value, so then you don't need to check if it's nil or not.

That can be done using the Hash.new constructor, compare:

my_hash = 
puts my_hash['no_existing_key'] #=> nil

my_hash = Hash.new()
puts my_hash['no_existing_key'] #=> 

You then can reduce your code to:

def create_a_hash_from_a_collection
 my_hash = Hash.new()

 collection_of_hashes.each do |key, value|
 my_hash[key] = value
 end

 my_hash
end

Since you are assigning value anyway, maybe you could use my_hash[key] = value || ?

So, if value to assign is nil, the value of that key becomes .