filters: allow sample(n) instead of just sample(1)

lib/jekyll/filters.rb

@@ -281,9 +281,9 @@ module Jekyll
       new_ary
     end
 
-    def sample(input)
+    def sample(input, num = 1)
       return input unless input.respond_to?(:sample)
-      input.sample(1)
+      input.sample(num)
     end
 
     # Convert an object into its String representation for debugging

site/_docs/templates.md

@@ -249,12 +249,15 @@ common tasks easier.
     <tr>
       <td>
         <p class="name"><strong>Sample</strong></p>
-        <p>Pick a random value from an array.</p>
+        <p>Pick a random value from an array. Optional: pick multiple values.</p>
       </td>
       <td class="align-center">
         <p>
          <code class="filter">{% raw %}{{ site.pages | sample }}{% endraw %}</code>
         </p>
+        <p>
+         <code class="filter">{% raw %}{{ site.pages | sample:2 }}{% endraw %}</code>
+        </p>
       </td>
     </tr>
   </tbody>

test/test_filters.rb

@@ -393,6 +393,13 @@ class TestFilters < JekyllUnitTest
         input = %w(hey there bernie)
         assert_includes input, @filter.sample(input)
       end
+
+      should "allow sampling of multiple values (n > 1)" do
+        input = %w(hey there bernie)
+        @filter.sample(input, 2).each do |val|
+          assert_includes val, input
+        end
+      end
     end
 
   end