javascript可用数组取代case格式化字符

这种方式代码更简洁：

    function getTypes(classid) {
        var types = [];
        types["1"] = "R";
        types["2"] = "S";
        types["3"] = "D";
        types["4"] = "C";
        types["5"] = "F";
        types["6"] = "H";
        return types[classid];
    }

可对比swich,case的方法:

    function getTypes(classid) {
    var str="";
    switch(classid)
    {
        case "1":
            str = "R";
            break;
        case "2":
            str = "S";
            break;
        case "3":
            str = "D";
            break;
        case "4":
            str = "C";
            break;
        case "5":
            str = "F";
            break;
        case "6":
            str = "H";
            break;
        default:
            str = "";
            break;
    }
    return str;
     }