From 1fdf578c17b38fc5391996d2016f4170bc3bf5ba Mon Sep 17 00:00:00 2001 From: Marcel Molina Date: Wed, 1 Mar 2006 20:32:10 +0000 Subject: Add Enumerable#group_by and Array#in_groups_of git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3726 5ecf4fe2-1ee6-0310-87b1-e25e094e27de --- activesupport/CHANGELOG | 25 +++++++++++++++++ activesupport/lib/active_support/core_ext/array.rb | 16 +++++++++++ .../lib/active_support/core_ext/enumerable.rb | 29 +++++++++++++++++++- activesupport/test/core_ext/array_ext_test.rb | 31 ++++++++++++++++++++++ activesupport/test/core_ext/enumerable_test.rb | 17 +++++++++++- 5 files changed, 116 insertions(+), 2 deletions(-) diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG index 7e20faecfa..0ed194591c 100644 --- a/activesupport/CHANGELOG +++ b/activesupport/CHANGELOG @@ -1,5 +1,30 @@ *SVN* +* Add Enumerable#group_by for grouping collections based on the result of some + block. Useful, for example, for grouping records by date. + + ex. + + latest_transcripts.group_by(&:day).each do |day, transcripts| + p "#{day} -> #{transcripts.map(&:class) * ', '}" + end + "2006-03-01 -> Transcript" + "2006-02-28 -> Transcript" + "2006-02-27 -> Transcript, Transcript" + "2006-02-26 -> Transcript, Transcript" + + Add Array#in_groups_of, for iterating over an array in groups of a certain + size. + + ex. + + %w(1 2 3 4 5 6 7).in_groups_of(3) {|g| p g} + ["1", "2", "3"] + ["4", "5", "6"] + ["7", nil, nil] + + [Marcel Molina Jr., Sam Stephenson] + * Added Kernel#daemonize to turn the current process into a daemon that can be killed with a TERM signal [DHH] * Add 'around' methods to Logger, to make it easy to log before and after messages for a given block as requested in #3809. [Michael Koziarski] Example: diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb index ddf2a369c1..897d73866c 100644 --- a/activesupport/lib/active_support/core_ext/array.rb +++ b/activesupport/lib/active_support/core_ext/array.rb @@ -2,4 +2,20 @@ require File.dirname(__FILE__) + '/array/conversions' class Array #:nodoc: include ActiveSupport::CoreExtensions::Array::Conversions + + # Iterate over an array in groups of a certain size, padding any remaining + # slots with specified value (nil by default). + # + # E.g. + # + # %w(1 2 3 4 5 6 7).in_groups_of(3) {|g| p g} + # ["1", "2", "3"] + # ["4", "5", "6"] + # ["7", nil, nil] + def in_groups_of(number, fill_with = nil, &block) + require 'enumerator' + collection = dup + collection << fill_with until collection.size.modulo(number).zero? + collection.each_slice(number, &block) + end end diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb index 49e1b7bb90..8a097dcd90 100644 --- a/activesupport/lib/active_support/core_ext/enumerable.rb +++ b/activesupport/lib/active_support/core_ext/enumerable.rb @@ -6,4 +6,31 @@ module Enumerable #:nodoc: end match end -end \ No newline at end of file + + # Collect an enumerable into sets, grouped by the result of a block. Useful, + # for example, for grouping records by date. + # + # e.g. + # + # latest_transcripts.group_by(&:day).each do |day, transcripts| + # p "#{day} -> #{transcripts.map(&:class) * ', '}" + # 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" + def group_by + inject([]) do |groups, element| + value = yield(element) + if (last_group = groups.last) && last_group.first == value + last_group.last << element + else + groups << [value, [element]] + end + groups + end + end +end diff --git a/activesupport/test/core_ext/array_ext_test.rb b/activesupport/test/core_ext/array_ext_test.rb index 159dc2a478..9e23eed450 100644 --- a/activesupport/test/core_ext/array_ext_test.rb +++ b/activesupport/test/core_ext/array_ext_test.rb @@ -34,3 +34,34 @@ class ArrayExtConversionTests < Test::Unit::TestCase assert_equal "one", ['one'].to_sentence end end + +class ArrayExtGroupingTests < Test::Unit::TestCase + def test_group_by_with_perfect_fit + groups = [] + ('a'..'i').to_a.in_groups_of(3) do |group| + groups << group + end + + assert_equal [%w(a b c), %w(d e f), %w(g h i)], groups + end + + def test_group_by_with_padding + groups = [] + ('a'..'g').to_a.in_groups_of(3) do |group| + groups << group + end + + assert_equal [%w(a b c), %w(d e f), ['g', nil, nil]], groups + end + + def test_group_by_pads_with_specified_values + groups = [] + + ('a'..'g').to_a.in_groups_of(3, false) do |group| + groups << group + end + + assert_equal [%w(a b c), %w(d e f), ['g', false, false]], groups + end + +end diff --git a/activesupport/test/core_ext/enumerable_test.rb b/activesupport/test/core_ext/enumerable_test.rb index 1fcaa9163e..6ca41f9116 100644 --- a/activesupport/test/core_ext/enumerable_test.rb +++ b/activesupport/test/core_ext/enumerable_test.rb @@ -12,4 +12,19 @@ class EnumerableTests < Test::Unit::TestCase assert_equal true, (1..10).first_match {|x| x > 9} assert_equal :aba, {:a => 10, :aba => 50, :bac => 40}.first_match {|k, v| k if v > 45} end -end \ No newline at end of file + + def test_group_by + names = %w(marcel sam david jeremy) + klass = Class.new + klass.send(:attr_accessor, :name) + objects = (1..50).inject([]) do |people,| + p = klass.new + p.name = names.sort_by { rand }.first + people << p + end + + objects.group_by {|object| object.name}.each do |name, group| + assert group.all? {|person| person.name == name} + end + end +end -- cgit v1.2.3