From f23f2bbdad7a15bec8812b029cb23c2117d7c63c Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby.or.jp>
Date: Fri, 21 Sep 2018 00:01:48 +0900
Subject: Implement `Array#union` which is introduced in Ruby2.6.

---
 mrbgems/mruby-array-ext/mrblib/array.rb | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'mrbgems/mruby-array-ext/mrblib/array.rb')

diff --git a/mrbgems/mruby-array-ext/mrblib/array.rb b/mrbgems/mruby-array-ext/mrblib/array.rb
index 4f676a121..8c2acc7ac 100644
--- a/mrbgems/mruby-array-ext/mrblib/array.rb
+++ b/mrbgems/mruby-array-ext/mrblib/array.rb
@@ -137,6 +137,25 @@ class Array
     ary.uniq! or ary
   end
 
+  ##
+  # call-seq:
+  #    ary.union(other_ary,...)  -> new_ary
+  #
+  # Set Union---Returns a new array by joining this array with
+  # <i>other_ary</i>, removing duplicates.
+  #
+  #    ["a", "b", "c"].union(["c", "d", "a"], ["a", "c", "e"])
+  #           #=> ["a", "b", "c", "d", "e"]
+  #
+  def union(*args)
+    ary = self.dup
+    args.each_with_index do |x,i|
+      ary.concat(x)
+      ary.uniq! if i % 20 == 0
+    end
+    ary.uniq! or ary
+  end
+
   ##
   # call-seq:
   #    ary & other_ary      -> new_ary
-- 
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