Merge pull request #23583 from brchristian/penultimate

Array.second_to_last and Array.third_to_last access methods

3 files changed, 20 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index bd333da081..3d4cc8fae6 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Add `Array#second_to_last` and `Array#third_to_last` methods.
+
+    *Brian Christian*
+
 *  Fix regression in `Hash#dig` for HashWithIndifferentAccess.
    *Jon Moss*
 
diff --git a/activesupport/lib/active_support/core_ext/array/access.rb b/activesupport/lib/active_support/core_ext/array/access.rb
index 3177d8498e..37d833887a 100644
--- a/activesupport/lib/active_support/core_ext/array/access.rb
+++ b/activesupport/lib/active_support/core_ext/array/access.rb
@@ -73,4 +73,18 @@ class Array
   def forty_two
     self[41]
   end
+
+  # Equal to <tt>self[-3]</tt>.
+  #
+  #   %w( a b c d e ).third_to_last # => "c"
+  def third_to_last
+    self[-3]
+  end
+
+  # Equal to <tt>self[-2]</tt>.
+  #
+  #   %w( a b c d e ).second_to_last # => "d"
+  def second_to_last
+    self[-2]
+  end
 end
diff --git a/activesupport/test/core_ext/array/access_test.rb b/activesupport/test/core_ext/array/access_test.rb
index 3f1e0c4cb4..1d834667f0 100644
--- a/activesupport/test/core_ext/array/access_test.rb
+++ b/activesupport/test/core_ext/array/access_test.rb
@@ -26,6 +26,8 @@ class AccessTest < ActiveSupport::TestCase
     assert_equal array[3], array.fourth
     assert_equal array[4], array.fifth
     assert_equal array[41], array.forty_two
+    assert_equal array[-3], array.third_to_last
+    assert_equal array[-2], array.second_to_last
   end
 
   def test_without