instance method `group_by`

Ruby on Rails 3.2.22.5

Since v2.2.3 Last seen in v3.2.22.5

Available in: v2.2.3 v2.3.18 v3.0.20 v3.1.12 v3.2.22.5

Compare with:

group_by()

Collect an enumerable into sets, grouped by the result of a block. Useful, for example, for grouping records by date.

Example:

latest_transcripts.group_by(&:day).each do |day, transcripts|
  p "#{day} -> #{transcripts.map(&:class).join(', ')}"
end
"2006-03-01 -> Transcript"
"2006-02-28 -> Transcript"
"2006-02-27 -> Transcript, Transcript"
"2006-02-26 -> Transcript, Transcript"
"2006-02-25 -> Transcript"
"2006-02-24 -> Transcript, Transcript"
"2006-02-23 -> Transcript"

Source

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 22
  def group_by
    return to_enum :group_by unless block_given?
    assoc = ActiveSupport::OrderedHash.new

    each do |element|
      key = yield(element)

      if assoc.has_key?(key)
        assoc[key] << element
      else
        assoc[key] = [element]
      end
    end

    assoc
  end

Defined in activesupport/lib/active_support/core_ext/enumerable.rb line 22 · View on GitHub · Improve this page · Find usages on GitHub

Defined in Enumerable

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