public function split_sentence_into_words($sentence)
{
$raw = preg_split('#\\s+#', $sentence);
$result = [];
foreach ($raw as $key => $word) {
if (strlen(trim($word)) > 0) {
$result[] = \Porter::stem($word);
}
}
return $result;
}
protected function stem(array &$tokens)
{
foreach ($tokens as $idx => $token) {
if (trim($token)) {
$tokens[$idx] = \Porter::stem($token);
} else {
unset($tokens[$idx]);
}
}
return $tokens;
}
