-module ActiveSupport #:nodoc:
- module CoreExtensions #:nodoc:
- module Hash #:nodoc:
- # Slice a hash to include only the given keys. This is useful for
- # limiting an options hash to valid keys before passing to a method:
- #
- # def search(criteria = {})
- # assert_valid_keys(:mass, :velocity, :time)
- # end
- #
- # search(options.slice(:mass, :velocity, :time))
- #
- # If you have an array of keys you want to limit to, you should splat them:
- #
- # valid_keys = [:mass, :velocity, :time]
- # search(options.slice(*valid_keys))
- module Slice
- # Returns a new hash with only the given keys.
- def slice(*keys)
- keys = keys.map! { |key| convert_key(key) } if respond_to?(:convert_key)
- hash = self.class.new
- keys.each { |k| hash[k] = self[k] if has_key?(k) }
- hash
- end
-
- # Replaces the hash with only the given keys.
- # Returns a hash contained the removed key/value pairs
- # {:a => 1, :b => 2, :c => 3, :d => 4}.slice!(:a, :b) # => {:c => 3, :d =>4}
- def slice!(*keys)
- keys = keys.map! { |key| convert_key(key) } if respond_to?(:convert_key)
- omit = slice(*self.keys - keys)
- hash = slice(*keys)
- replace(hash)
- omit
- end
- end
- end
- end
-end
-