select only some keys from hash ruby code example

Example 1: ruby hash pick

> { one: 1, two: 2, three: 3 }.slice(:one, :two)
=> {:one=>1, :two=>2}

Example 2: rails filter hashes by key value

{ :a => 1, :b => 2, :c => 3 }.select { |k, v| k != :a && v.even? } # => { :b => 2 }