dump() 把数组以数组格式数组，有益于调试

function dump($vars, $label = '', $return = false){
    if (ini_get('html_errors')) {
        $content = "<pre> ";
        if ($label != '') {
            $content .= "<strong>{$label} :</strong> ";
        }
        $content .= htmlspecialchars(print_r($vars, true));
        $content .= " </pre> ";
    } else {
        $content = $label . " : " . print_r($vars, true);
    }
    if ($return) { return $content; }
    echo $content;
    return null;
}

array_remove_empty()去除数组中为空的元素

function array_remove_empty(& $arr, $trim = true){
    foreach ($arr as $key => $value) {
        if (is_array($value)) {
            array_remove_empty($arr[$key]);
        } else {
            $value = trim($value);
            if ($value == '') {
                unset($arr[$key]);
            } elseif ($trim) {
                $arr[$key] = $value;
            }
        }
    }
}

array_chunk() php默认函数 作用是把函数平均分组