Ruby's Collect method

Ruby's collect method is part of the Enumerable mixin.
A mixin which provides very useful and powerful methods for collection objects.
It allows you to transform each element of your collection object into something else.

			
					hash = Hash[array.collect { |item| [item, ""] } ]

Let's see the small example with the collect method.

			
					[1, 2, 3].collect{ |num| num * 4 }

array to hash ruby

			
					names = %w(adam alice benny matt)
hash = Hash[names.collect { |item| [item, item.capitalize()] } ]

Output

			
					# {"adam"=>"Adam", "alice"=>"Alice", "benny"=>"Benny", "matt"=>"Matt"}

			
					arr = [1, 2, 3]
Hash[arr.map{|n| [n, n*5]}]

Output

			
					# {1=>5, 2=>10, 3=>15}

			
					arr = ["California", "London", "Washington", "Paris"]

			
					domains = {
  "de" => "Germany",
  "es" => "Spanish",
  "us" => "United States",
  "no" => "Norway"
}

Reference values by key
Anything can be the key to a hash like Strings, symbols, Integers, Floats, even other arrays or hashes.