diff --git a/parsecsv.lib.php b/parsecsv.lib.php
index beffd1e..4ea9e08 100644
--- a/parsecsv.lib.php
+++ b/parsecsv.lib.php
@@ -730,6 +730,9 @@ class parseCSV {
 
             $this->sort_reverse ? krsort($rows, $sort_type) : ksort($rows, $sort_type);
 
+            // Avoid issues with mixing string and integer keys:
+            $rows = array_values($rows);
+
             if ($this->offset !== null || $this->limit !== null) {
                 $rows = array_slice($rows, ($this->offset === null ? 0 : $this->offset), $this->limit, true);
             }
diff --git a/tests/properties/BaseClass.php b/tests/properties/BaseClass.php
new file mode 100644
index 0000000..4d9c420
--- /dev/null
+++ b/tests/properties/BaseClass.php
@@ -0,0 +1,31 @@
+<?php
+
+class BaseClass extends PHPUnit\Framework\TestCase {
+
+    /**
+     * CSV
+     * The parseCSV object
+     *
+     * @access protected
+     * @var parseCSV
+     */
+    protected $csv;
+
+    /**
+     * Setup
+     * Setup our test environment objects
+     *
+     * @access public
+     */
+    public function setUp() {
+        $this->csv = new parseCSV();
+    }
+
+    protected function _compareWithExpected($expected) {
+        $this->csv->auto(__DIR__ . '/../../examples/_books.csv');
+        $actual = array_map(function ($row) {
+            return $row['title'];
+        }, $this->csv->data);
+        $this->assertEquals($expected, $actual);
+    }
+}
diff --git a/tests/properties/SortByTest.php b/tests/properties/SortByTest.php
new file mode 100644
index 0000000..c26d4bb
--- /dev/null
+++ b/tests/properties/SortByTest.php
@@ -0,0 +1,56 @@
+<?php
+
+class SortByTest extends BaseClass {
+
+    public function testSortByRating() {
+        $this->csv->sort_by = 'rating';
+        $this->_compareWithExpected([
+            // Rating 0
+            'The Killing Kind',
+            'The Third Secret',
+
+            // Rating 3
+            'The Last Templar',
+            'The Broker (Paperback)',
+            'Without Blood (Paperback)',
+
+            // Rating 4
+            'Deception Point (Paperback)',
+            'The Rule of Four (Paperback)',
+            'The Da Vinci Code (Hardcover)',
+
+            // Rating 5
+            'State of Fear (Paperback)',
+            'Prey',
+            'Digital Fortress : A Thriller (Mass Market Paperback)',
+            'Angels & Demons (Mass Market Paperback)',
+        ]);
+    }
+
+    public function testReverseSortByRating() {
+        $this->csv->sort_by = 'rating';
+        $this->csv->sort_reverse = true;
+        $this->_compareWithExpected([
+
+            // Rating 5
+            'Digital Fortress : A Thriller (Mass Market Paperback)',
+            'Prey',
+            'State of Fear (Paperback)',
+            'Angels & Demons (Mass Market Paperback)',
+
+            // Rating 4
+            'The Da Vinci Code (Hardcover)',
+            'The Rule of Four (Paperback)',
+            'Deception Point (Paperback)',
+
+            // Rating 3
+            'The Broker (Paperback)',
+            'The Last Templar',
+            'Without Blood (Paperback)',
+
+            // Rating 0
+            'The Third Secret',
+            'The Killing Kind',
+        ]);
+    }
+}