- strstr: documentation ( source)
<?php
$array = ["index.php","assets","README.md","OpgaveBo","Opgave8","Opgave6","Opgave3","Opgave2","Opgave11","Opgave10","Opgave1",".git"];
foreach($array as $file) {
if (strstr($file, 'Opgave')) {
echo $file."\n";
}
}