diff --git a/.gitignore b/.gitignore
index d9a7098..8bf7269 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,5 @@ vendor
 .idea
 
 node_modules
-.usdocker
\ No newline at end of file
+.usdocker
+.phpunit.result.cache
diff --git a/src/RowOutput.php b/src/RowOutput.php
new file mode 100644
index 0000000..2ec52a4
--- /dev/null
+++ b/src/RowOutput.php
@@ -0,0 +1,80 @@
+<?php
+
+namespace ByJG\AnyDataset\Core;
+use Closure;
+
+class RowOutput
+{
+    const FORMAT = 'format';
+    const CUSTOM = 'custom';
+
+    protected $fieldList = [];
+
+    public static function getInstance()
+    {
+        return new RowOutput();
+    }
+
+    public function print($row, $field)
+    {
+        if (!isset($this->fieldList[$field])) {
+            return $row->get($field);
+        }
+
+        $data = $this->fieldList[$field];
+
+        switch ($data[0]) {
+            case self::FORMAT:
+                return $this->formatPattern($row, $field, $data[1]);
+            case self::CUSTOM:
+                return $this->formatCustom($row, $field, $data[1]);
+        }
+    }
+
+    public function apply($row)
+    {
+        foreach ($this->fieldList as $key => $value) {
+            $row->set($key, $this->print($row, $key));
+        }
+    }
+
+    protected function formatPattern($row, $field, $pattern)
+    {
+        $rowParsed = $row->toArray();
+        foreach ($rowParsed as $key => $value) {
+            $rowParsed['{' . $key . '}'] = $value;
+            unset($rowParsed[$key]);
+        }
+
+        return strtr($pattern, $rowParsed);
+    }
+
+    protected function formatCustom($row, $field, $closure)
+    {
+        return $closure($row, $field, $row->get($field));
+    }
+
+    /**
+     * @param string $field
+     * @param string $pattern
+     * @return RowOutput
+     */
+    public function addFormat($field, $pattern)
+    {
+        $this->fieldList[$field] = [ self::FORMAT,  $pattern ];
+        return $this;
+    }
+
+    /**
+     * Undocumented function
+     *
+     * @param string $field
+     * @param Closure $closure
+     * @return RowOutput
+     */
+    public function addCustomFormat($field, Closure $closure)
+    {
+        $this->fieldList[$field] = [ self::CUSTOM, $closure ];
+        return $this;
+    }
+}
\ No newline at end of file
diff --git a/tests/RowOutputTest.php b/tests/RowOutputTest.php
new file mode 100644
index 0000000..4650232
--- /dev/null
+++ b/tests/RowOutputTest.php
@@ -0,0 +1,90 @@
+<?php
+
+namespace Tests\AnyDataset\Dataset;
+
+use ByJG\AnyDataset\Core\Row;
+use ByJG\AnyDataset\Core\RowValidator;
+use PHPUnit\Framework\TestCase;
+use ByJG\AnyDataset\Core\RowOutput;
+
+class RowOutputTest extends TestCase
+{
+
+    public function testFormatPattern()
+    {
+        $row1 = new Row([
+            "field1" => 10,
+            "field2" => "test",
+            "field3" => 20.30,
+            "field4" => "2021-11-20"
+        ]);
+
+        $row2 = new Row([
+            "field1" => 1,
+            "field2" => "OK",
+            "field3" => 3,
+        ]);
+
+        $formatter = RowOutput::getInstance()
+            ->addFormat("field1", "Test {field1}")
+            ->addFormat("field2", "Showing {field2} and {field3}");
+
+        $this->assertEquals("Test 10", $formatter->print($row1, "field1"));
+        $this->assertEquals("Showing test and 20.3", $formatter->print($row1, "field2"));
+        $this->assertEquals("20.30", $formatter->print($row1, "field3"));
+
+        $this->assertEquals("Test 1", $formatter->print($row2, "field1"));
+        $this->assertEquals("Showing OK and 3", $formatter->print($row2, "field2"));
+        $this->assertEquals("3", $formatter->print($row2, "field3"));
+    }
+
+    public function testFormatCustom()
+    {
+        $row = new Row([
+            "field1" => 10,
+            "field2" => "test",
+            "field3" => 20.30,
+            "field4" => "2021-11-20"
+        ]);
+
+        $formatter = RowOutput::getInstance()
+            ->addCustomFormat("field1", function ($row, $field, $value) {
+                return $value * 4;
+            })
+            ->addCustomFormat("field3", function ($row, $field, $value) {
+                return "$field x 3 = " . ($value * 3);
+            });
+
+        $this->assertEquals("40", $formatter->print($row, "field1"));
+        $this->assertEquals("field3 x 3 = 60.9", $formatter->print($row, "field3"));
+        $this->assertEquals("2021-11-20", $formatter->print($row, "field4"));
+    }
+
+    public function testApply()
+    {
+        $row = new Row([
+            "field1" => 10,
+            "field2" => "test",
+            "field3" => 20.30,
+            "field4" => "2021-11-20"
+        ]);
+
+        $formatter = RowOutput::getInstance()
+            ->addFormat("field1", "Value: {field1}")
+            ->addCustomFormat("field3", function ($row, $field, $value) {
+                return "$field x 3 = " . ($value * 3);
+            });
+
+        $this->assertEquals("10", $row->get("field1"));
+        $this->assertEquals("test", $row->get("field2"));
+        $this->assertEquals("20.30", $row->get("field3"));
+        $this->assertEquals("2021-11-20", $row->get("field4"));
+
+        $formatter->apply($row);
+    
+        $this->assertEquals("Value: 10", $row->get("field1"));
+        $this->assertEquals("test", $row->get("field2"));
+        $this->assertEquals("field3 x 3 = 60.9", $row->get("field3"));
+        $this->assertEquals("2021-11-20", $row->get("field4"));
+    }
+}
diff --git a/tests/RowValidatorTest.php b/tests/RowValidatorTest.php
index 4bacc7a..4aa45cd 100644
--- a/tests/RowValidatorTest.php
+++ b/tests/RowValidatorTest.php
@@ -6,10 +6,6 @@
 use ByJG\AnyDataset\Core\RowValidator;
 use PHPUnit\Framework\TestCase;
 
-require_once "Sample/ModelPublic.php";
-require_once "Sample/ModelGetter.php";
-require_once "Sample/ModelPropertyPattern.php";
-
 class RowValidatorTest extends TestCase
 {