You can try it like this:
<?php
function readFoldersFiles() {
$arrayFolders = array("Circolari", "Comunicazioni varie", "Consuntivi gestione", "estrattor conto", "Preventivi gestione", "Regolamento condominio", "Verbali assemblee");
foreach ($arrayFolders as $folder) {
$folderPath = '../pdf/' . $GLOBALS['condominio'] . '/' . $folder;
if (file_exists($folderPath) && is_dir($folderPath)) {
continue;
}
mkdir($folderPath);
}
}