1 files changed, 18 insertions, 4 deletions
diff --git a/activesupport/lib/active_support/core_ext/array/random_access.rb b/activesupport/lib/active_support/core_ext/array/random_access.rb
index 67c322daea..7a4836cecd 100644
--- a/activesupport/lib/active_support/core_ext/array/random_access.rb
+++ b/activesupport/lib/active_support/core_ext/array/random_access.rb
@@ -1,6 +1,20 @@
 class Array
-  # Returns a random element from the array.
-  def random_element
-    self[Kernel.rand(length)]
-  end
+  # Backport of Array#sample based on Marc-Andre Lafortune's http://github.com/marcandre/backports/
+  def sample(n=nil)
+    return self[Kernel.rand(size)] if n.nil?
+    n = n.to_int
+  rescue Exception => e
+    raise TypeError, "Coercion error: #{n.inspect}.to_int => Integer failed:\n(#{e.message})"
+  else
+    raise TypeError, "Coercion error: obj.to_int did NOT return an Integer (was #{n.class})" unless n.kind_of? Integer
+    raise ArgumentError, "negative array size" if n < 0
+    n = size if n > size
+    result = Array.new(self)
+    n.times do |i|
+      r = i + Kernel.rand(size - i)
+      result[i], result[r] = result[r], result[i]
+    end
+    result[n..size] = []
+    result
+  end unless method_defined? :sample
 end
 \ No newline at end of file