从文件名获取扩展名，如变量[duplicate]

$ext = pathinfo($filename, PATHINFO_EXTENSION);

$info = pathinfo($file);

$info[\'extension\']

function get_file_extension($filename)
{
    /*
     * \".\" for extension should be available and not be the first character
     * so position should not be false or 0.
     */
    $lastDotPos = strrpos($fileName, \'.\');
    if ( !$lastDotPos ) return false;
    return substr($fileName, $lastDotPos+1);
}

preg_match(\'/\\.([^\\.]+)$/\', $filename);

$path_info = pathinfo($filename);

echo $path_info[\'extension\'], \"\\n\";

$filename = \"file.m.e.ext\";
$filenameitems = explode(\".\", $filename);

echo $filenameitems[count($filenameitems) - 1]; // .ext
// or echo $filenameitem[-1];