proper user of vectorizer and working example:

Author: akondas

examples/LanguageDetection.php

@@ -6,25 +6,32 @@
 use Phpml\Dataset\ArrayDataset;
 use Phpml\FeatureExtraction\TokenCountVectorizer;
 use Phpml\Tokenization\WordTokenizer;
-use Phpml\CrossValidation\RandomSplit;
+use Phpml\CrossValidation\StratifiedRandomSplit;
+use Phpml\FeatureExtraction\TfIdfTransformer;
 use Phpml\Metric\Accuracy;
 use Phpml\Classification\SVC;
 use Phpml\SupportVectorMachine\Kernel;
 
 $dataset = new CsvDataset('data/languages.csv', 1);
 $vectorizer = new TokenCountVectorizer(new WordTokenizer());
+$tfIdfTransformer = new TfIdfTransformer();
 
 $samples = [];
 foreach ($dataset->getSamples() as $sample) {
     $samples[] = $sample[0];
 }
 
+$vectorizer->fit($samples);
 $vectorizer->transform($samples);
+
+$tfIdfTransformer->fit($samples);
+$tfIdfTransformer->transform($samples);
+
 $dataset = new ArrayDataset($samples, $dataset->getTargets());
 
-$randomSplit = new RandomSplit($dataset, 0.25);
+$randomSplit =  new StratifiedRandomSplit($dataset, 0.1);
 
-$classifier = new SVC(Kernel::RBF, 100);
+$classifier = new SVC(Kernel::RBF, 10000);
 $classifier->train($randomSplit->getTrainSamples(), $randomSplit->getTrainLabels());
 
 $predictedLabels = $classifier->predict($randomSplit->getTestSamples());