Add `Array#difference` method from Ruby2.6.

2 files changed, 24 insertions, 0 deletions

diff --git a/mrbgems/mruby-array-ext/mrblib/array.rb b/mrbgems/mruby-array-ext/mrblib/array.rb
index fc5d87f2c..f9f232321 100644
--- a/mrbgems/mruby-array-ext/mrblib/array.rb
+++ b/mrbgems/mruby-array-ext/mrblib/array.rb
@@ -126,6 +126,22 @@ class Array
 
   ##
   # call-seq:
+  #    ary.difference(other_ary1, other_ary2, ...)   -> new_ary
+  #
+  # Returns a new array that is a copy of the original array, removing all
+  # occurences of any item that also appear in +other_ary+. The order is
+  # preserved from the original array.
+  #
+  def difference(*args)
+    ary = self.dup
+    args.each do |x|
+      ary = self - x
+    end
+    ary
+  end
+
+  ##
+  # call-seq:
   #    ary & other_ary      -> new_ary
   #
   # Set Intersection---Returns a new array
diff --git a/mrbgems/mruby-array-ext/test/array.rb b/mrbgems/mruby-array-ext/test/array.rb
index a4e328b71..029325aab 100644
--- a/mrbgems/mruby-array-ext/test/array.rb
+++ b/mrbgems/mruby-array-ext/test/array.rb
@@ -93,6 +93,14 @@ assert("Array#union") do
   assert_equal [1, 2, 3, 4, 5], a.union(b,c)
 end
 
+assert("Array#difference") do
+  a = [1, 2, 3, 1]
+  b = [1, 4]
+  c = [1, 5]
+
+  assert_equal [2, 3], a.difference(b,c)
+end
+
 assert("Array#&") do
   a = [1, 2, 3, 1]
   b = [1, 4]