diff --git a/src/Enum/Relation.php b/src/Enum/Relation.php
index b3fd844..f86cbf2 100644
--- a/src/Enum/Relation.php
+++ b/src/Enum/Relation.php
@@ -49,4 +49,14 @@ class Relation
      * "Contains" unary comparator
      */
     const CONTAINS = 7;
+
+    /**
+     * "In" unary comparator
+     */
+    const IN = 8;
+
+    /**
+     * "Not In" unary comparator
+     */
+    const NOT_IN = 9;
 }
diff --git a/src/IteratorFilter.php b/src/IteratorFilter.php
index c1d172e..7092027 100644
--- a/src/IteratorFilter.php
+++ b/src/IteratorFilter.php
@@ -114,6 +114,14 @@ private function evalString(Row $singleRow)
                         $result[$pos] = $result[$pos] && (strpos(is_null($valueparam) ? "" : $valueparam, $value) === 0);
                         break;
 
+                    case Relation::IN:
+                        $result[$pos] = $result[$pos] && in_array($valueparam, $value);
+                        break;
+
+                    case Relation::NOT_IN:
+                        $result[$pos] = $result[$pos] && !in_array($valueparam, $value);
+                        break;
+
                     default: // Relation::CONTAINS:
                         $result[$pos] = $result[$pos] && (strpos(is_null($valueparam) ? "" : $valueparam, $value) !== false);
                         break;
@@ -129,7 +137,7 @@ private function evalString(Row $singleRow)
     /**
      * @param string $name Field name
      * @param int $relation Relation enum
-     * @param string $value Field string value
+     * @param string|array $value Field string value
      * @return IteratorFilter
      * @desc Add a single string comparison to filter.
      */
diff --git a/src/IteratorFilterFormatter.php b/src/IteratorFilterFormatter.php
index 5f0572f..ccab474 100644
--- a/src/IteratorFilterFormatter.php
+++ b/src/IteratorFilterFormatter.php
@@ -10,7 +10,7 @@ abstract class IteratorFilterFormatter
      *
      * @param string $name
      * @param string $relation
-     * @param string $value
+     * @param string|array $value
      * @param array $param
      * @return string
      */
diff --git a/src/IteratorFilterXPathFormatter.php b/src/IteratorFilterXPathFormatter.php
index b5c8553..c7c575b 100644
--- a/src/IteratorFilterXPathFormatter.php
+++ b/src/IteratorFilterXPathFormatter.php
@@ -28,7 +28,9 @@ public function getRelation($name, $relation, $value, &$param)
      {
           $str = is_numeric($value) ? "" : "'";
           $field = "field[@name='" . $name . "'] ";
-          $value = " $str$value$str ";
+          if (is_string($value)) {
+              $value = " $str$value$str ";
+          }
 
           switch ($relation) {
                case Relation::EQUAL:
@@ -59,6 +61,12 @@ public function getRelation($name, $relation, $value, &$param)
                     $return = " starts-with($field, $value) ";
                     break;
 
+                case Relation::IN:
+                    throw new \InvalidArgumentException('XPath does not support IN');
+
+                case Relation::NOT_IN:
+                    throw new \InvalidArgumentException('XPath does not support NOT IN');
+
                default: // Relation::CONTAINS:
                     $return = " contains($field, $value) ";
                     break;
diff --git a/tests/IteratorFilterAnydatasetTest.php b/tests/IteratorFilterAnydatasetTest.php
new file mode 100644
index 0000000..97e8447
--- /dev/null
+++ b/tests/IteratorFilterAnydatasetTest.php
@@ -0,0 +1,129 @@
+<?php
+
+namespace Tests\AnyDataset\Dataset;
+
+use ByJG\AnyDataset\Core\IteratorFilter;
+use ByJG\AnyDataset\Core\IteratorFilterXPathFormatter;
+use ByJG\AnyDataset\Core\Row;
+use ByJG\AnyDataset\Core\Enum\Relation;
+use PHPUnit\Framework\TestCase;
+
+class IteratorFilterAnydatasetTest extends TestCase
+{
+
+    /**
+     * @var IteratorFilter
+     */
+    protected $object;
+
+    /**
+     * Sets up the fixture, for example, opens a network connection.
+     * This method is called before a test is executed.
+     */
+    protected function setUp(): void
+    {
+        $this->object = new IteratorFilter();
+    }
+
+    public function testMatch()
+    {
+
+        $collection = [
+            $row1 = new Row(
+                [
+                    'id'   => 1,
+                    'field' => 'value1',
+                    'field2' => 'value2',
+                    'val' => 50,
+                ]
+            ),
+            $row2 = new Row(
+                [
+                    'id'   => 2,
+                    'field' => 'other1',
+                    'field2' => 'other2',
+                    'val' => 80,
+                ]
+            ),
+            $row3 = new Row(
+                [
+                    'id'   => 3,
+                    'field' => 'last1',
+                    'field2' => 'last2',
+                    'val' => 30,
+                ]
+            ),
+            $row4 = new Row(
+                [
+                    'id'   => 4,
+                    'field' => 'xy',
+                    'field2' => 'zy',
+                    'val' => 10,
+                ]
+            ),
+        ];
+
+        $this->assertEquals($collection, $this->object->match($collection));
+
+        $this->object->addRelation('field2', Relation::EQUAL, 'other2');
+        $this->assertEquals([$row2], $this->object->match($collection));
+
+        $this->object->addRelationOr('field', Relation::EQUAL, 'last1');
+        $this->assertEquals([$row2, $row3], $this->object->match($collection));
+
+
+        //------------------------
+
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('field', Relation::EQUAL, 'last1');
+        $this->object->addRelation('field2', Relation::EQUAL, 'last2');
+        $this->assertEquals([$row3], $this->object->match($collection));
+
+        // Test Greater Than
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::GREATER_THAN, 50);
+        $this->assertEquals([$row2], $this->object->match($collection));
+
+        // Test Less Than
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::LESS_THAN, 50);
+        $this->assertEquals([$row3, $row4], $this->object->match($collection));
+
+        // Test Greater or Equal Than
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::GREATER_OR_EQUAL_THAN, 50);
+        $this->assertEquals([$row1, $row2], $this->object->match($collection));
+
+        // Test Less or Equal Than
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::LESS_OR_EQUAL_THAN, 50);
+        $this->assertEquals([$row1, $row3, $row4], $this->object->match($collection));
+
+        // Test Not Equal
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::NOT_EQUAL, 50);
+        $this->assertEquals([$row2, $row3, $row4], $this->object->match($collection));
+
+        // Test Starts With
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('field', Relation::STARTS_WITH, 'la');
+        $this->assertEquals([$row3], $this->object->match($collection));
+
+        // Test Contains
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('field', Relation::CONTAINS, '1');
+        $this->assertEquals([$row1, $row2, $row3], $this->object->match($collection));
+
+        // Test In
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::IN, [10, 30, 50]);
+        $this->assertEquals([$row1, $row3, $row4], $this->object->match($collection));
+
+        // Test Not In
+        $this->object = new IteratorFilter();
+        $this->object->addRelation('val', Relation::NOT_IN, [10, 30, 50]);
+        $this->assertEquals([$row2], $this->object->match($collection));
+    }
+
+
+}
diff --git a/tests/IteratorFilterTest.php b/tests/IteratorFilterXPathTest.php
similarity index 67%
rename from tests/IteratorFilterTest.php
rename to tests/IteratorFilterXPathTest.php
index ba953ff..27c4928 100644
--- a/tests/IteratorFilterTest.php
+++ b/tests/IteratorFilterXPathTest.php
@@ -8,7 +8,7 @@
 use ByJG\AnyDataset\Core\Enum\Relation;
 use PHPUnit\Framework\TestCase;
 
-class IteratorFilterTest extends TestCase
+class IteratorFilterXPathTest extends TestCase
 {
 
     /**
@@ -51,47 +51,6 @@ public function testGetXPath()
         );
     }
 
-    public function testMatch()
-    {
-
-        $collection = [
-            $row1 = new Row(
-                [
-                    'field' => 'value1',
-                    'field2' => 'value2'
-                ]
-            ),
-            $row2 = new Row(
-                [
-                    'field' => 'other1',
-                    'field2' => 'other2'
-                ]
-            ),
-            $row3 = new Row(
-                [
-                    'field' => 'last1',
-                    'field2' => 'last2'
-                ]
-            )
-        ];
-
-        $this->assertEquals($collection, $this->object->match($collection));
-
-        $this->object->addRelation('field2', Relation::EQUAL, 'other2');
-        $this->assertEquals([ $row2], $this->object->match($collection));
-
-        $this->object->addRelationOr('field', Relation::EQUAL, 'last1');
-        $this->assertEquals([ $row2, $row3], $this->object->match($collection));
-
-
-        //------------------------
-
-        $this->object = new IteratorFilter();
-        $this->object->addRelation('field', Relation::EQUAL, 'last1');
-        $this->object->addRelation('field2', Relation::EQUAL, 'last2');
-        $this->assertEquals([ $row3], $this->object->match($collection));
-    }
-
     public function testAddRelationOr()
     {
         $this->object->addRelation('field', Relation::EQUAL, 'test');
@@ -114,4 +73,18 @@ public function testGroup()
             $this->object->format(new IteratorFilterXPathFormatter())
         );
     }
+
+    public function testIn()
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->object->addRelation('field', Relation::IN, ['test', 'test2']);
+        $this->object->format(new IteratorFilterXPathFormatter());
+    }
+
+    public function testNotIn()
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->object->addRelation('field', Relation::NOT_IN, ['test', 'test2']);
+        $this->object->format(new IteratorFilterXPathFormatter());
+    }
 }