diff --git a/src/Phpml/CrossValidation/RandomSplit.php b/src/Phpml/CrossValidation/RandomSplit.php
index 4e2ecc9..c5a24bd 100644
--- a/src/Phpml/CrossValidation/RandomSplit.php
+++ b/src/Phpml/CrossValidation/RandomSplit.php
@@ -31,8 +31,8 @@ class RandomSplit
 
     /**
      * @param Dataset $dataset
-     * @param float $testSize
-     * @param int $seed
+     * @param float   $testSize
+     * @param int     $seed
      *
      * @throws InvalidArgumentException
      */
@@ -47,8 +47,8 @@ class RandomSplit
         $labels = $dataset->getLabels();
         $datasetSize = count($samples);
 
-        for($i=$datasetSize; $i>0; $i--) {
-            $key = mt_rand(0, $datasetSize-1);
+        for ($i = $datasetSize; $i > 0; --$i) {
+            $key = mt_rand(0, $datasetSize - 1);
             $setName = count($this->testSamples) / $datasetSize >= $testSize ? 'train' : 'test';
 
             $this->{$setName.'Samples'}[] = $samples[$key];
diff --git a/src/Phpml/Dataset/ArrayDataset.php b/src/Phpml/Dataset/ArrayDataset.php
index 580df0a..d117122 100644
--- a/src/Phpml/Dataset/ArrayDataset.php
+++ b/src/Phpml/Dataset/ArrayDataset.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare (strict_types = 1);
 
 namespace Phpml\Dataset;
 
@@ -7,7 +8,6 @@ use Phpml\Exception\InvalidArgumentException;
 
 class ArrayDataset implements Dataset
 {
-
     /**
      * @var array
      */
@@ -34,7 +34,6 @@ class ArrayDataset implements Dataset
         $this->labels = $labels;
     }
 
-
     /**
      * @return array
      */
@@ -50,5 +49,4 @@ class ArrayDataset implements Dataset
     {
         return $this->labels;
     }
-    
 }
diff --git a/src/Phpml/Dataset/CsvDataset.php b/src/Phpml/Dataset/CsvDataset.php
index de540c9..e6dafd2 100644
--- a/src/Phpml/Dataset/CsvDataset.php
+++ b/src/Phpml/Dataset/CsvDataset.php
@@ -14,11 +14,13 @@ class CsvDataset extends ArrayDataset
     protected $filepath;
 
     /**
-     * @param string|null $filepath
+     * @param string $filepath
+     * @param int    $features
+     * @param bool   $headingRow
      *
      * @throws DatasetException
      */
-    public function __construct(string $filepath = null)
+    public function __construct(string $filepath, int $features, bool $headingRow = true)
     {
         if (!file_exists($filepath)) {
             throw DatasetException::missingFile(basename($filepath));
@@ -28,11 +30,11 @@ class CsvDataset extends ArrayDataset
         if (($handle = fopen($filepath, 'r')) !== false) {
             while (($data = fgetcsv($handle, 1000, ',')) !== false) {
                 ++$row;
-                if ($row == 1) {
+                if ($headingRow && $row == 1) {
                     continue;
                 }
-                $this->samples[] = array_slice($data, 0, 4);
-                $this->labels[] = $data[4];
+                $this->samples[] = array_slice($data, 0, $features);
+                $this->labels[] = $data[$features];
             }
             fclose($handle);
         } else {
diff --git a/src/Phpml/Dataset/Demo/Iris.php b/src/Phpml/Dataset/Demo/Iris.php
index 5a4789e..923f0ba 100644
--- a/src/Phpml/Dataset/Demo/Iris.php
+++ b/src/Phpml/Dataset/Demo/Iris.php
@@ -14,12 +14,9 @@ use Phpml\Dataset\CsvDataset;
  */
 class Iris extends CsvDataset
 {
-    /**
-     * @param string|null $filepath
-     */
-    public function __construct(string $filepath = null)
+    public function __construct()
     {
         $filepath = dirname(__FILE__).'/../../../../data/iris.csv';
-        parent::__construct($filepath);
+        parent::__construct($filepath, 4, true);
     }
 }
diff --git a/tests/Phpml/CrossValidation/RandomSplitTest.php b/tests/Phpml/CrossValidation/RandomSplitTest.php
index cbbd497..e6ae30e 100644
--- a/tests/Phpml/CrossValidation/RandomSplitTest.php
+++ b/tests/Phpml/CrossValidation/RandomSplitTest.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare (strict_types = 1);
 
 namespace tests\Phpml\CrossValidation;
 
@@ -8,7 +9,6 @@ use Phpml\Dataset\ArrayDataset;
 
 class RandomSplitTest extends \PHPUnit_Framework_TestCase
 {
-
     /**
      * @expectedException \Phpml\Exception\InvalidArgumentException
      */
@@ -91,5 +91,4 @@ class RandomSplitTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($randomSplit->getTrainSamples()[0][0], $randomSplit->getTrainLabels()[0]);
         $this->assertEquals($randomSplit->getTrainSamples()[1][0], $randomSplit->getTrainLabels()[1]);
     }
-    
-}
\ No newline at end of file
+}