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
Example 1
names = %w(adam alice benny matt) hash = Hash[names.collect { |item| [item, item.capitalize()] } ]
Output
# {"adam"=>"Adam", "alice"=>"Alice", "benny"=>"Benny", "matt"=>"Matt"}
Example 2 ruby hash.map
arr = [1, 2, 3] Hash[arr.map{|n| [n, n*5]}]
Output
# {1=>5, 2=>10, 3=>15}
Array vs Hashes
- Arrays are the way to Store values sequentially.
arr = ["California", "London", "Washington", "Paris"]
- Reference values by key
- Hashes are the way to store values by name (key).
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.