Testing string length within FTP

for($i = 0; $i < $countList; $i++){
$strDirName = substr($arrList[$i], 47, 8);
if(strlen(chop($strDirName)) == 8){
echo $theDirectory.$strDirName."<br>";
}
}

I am trying to check for $strDirName length, but the echo returns all
file names within the directory regardless of length (was going to use
is_dir, but cannot on remote file system). I know that all remote
directory names are 8 characters in length, but returning this is not
working. I hope I am making sense. TIA!