Building a hash in a conditional way

Question

I am using Ruby on Rails 3.0.10 and I would like to build an hash key\\value pairs in a conditional way. That is, I would like to add a key and its related value if a condition

Answer 1

A functional approach:

hash = {
  :key1 => 1,
  :key2 => (2 if condition),
  :key3 => 3,
}.compact 

If Hash.compact is not available in your environment, write .reject { |k, v| v.nil? }