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

Using fetch can be useful if you're populating a hash from optional attributes somewhere else. Look at this example:

def create_watchable_data(attrs = {})
  return WatchableData.new({
    id:             attrs.fetch(:id, '/catalog/titles/breaking_bad_2_737'),
    titles:         attrs.fetch(:titles, ['737']),
    url:            attrs.fetch(:url, 'http://www.netflix.com/shows/breaking_bad/3423432'),
    year:           attrs.fetch(:year, '1993'),
    watchable_type: attrs.fetch(:watchable_type, 'Show'),
    season_title:   attrs.fetch(:season_title, 'Season 2'),
    show_title:     attrs.fetch(:id, 'Breaking Bad')
  })
end