PHP数组转字符串后仍保留数组格式

    function arr2str($arr, $t = 0)
    {
        $str = null;
        $pad = str_pad("", $t, "\t");

        foreach ($arr as $k => $v) {
            if (is_array($v)) {
                if (is_string($k)) {
                    $str .= $pad . "‘" . $k . "‘=>array(\n" . arr2str($v, $t + 1) . $pad . "),\n";
                } else {
                    $str .= $pad . "array(\n" . arr2str($v, $t + 1) . $pad . "),\n";
                }
            } else {
                if (is_string($k)) {
                    $str .= $pad . "‘" . $k . "‘=>‘" . $v . "‘,\n";
                } else {
                    $str .= $pad . "‘" . $v . "‘,\n";
                }
            }
        }
        return $str;
    }