Question

我是编程新手，但如果用户选择了元素，我需要按元素分组;因此，我不确定我的小组将包含多少元素。因此，我这样做是为了计算所选元素的数量，然后创建另一个语句，该语句创建表示所需元素数量的正确Group by语句。

它有效，但它看起来很笨重，我想看看是否有更好的方法可以做到这一点？

int totalOutPuts = 0;
totalOutPuts = endbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = coursebox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = departmentbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = callbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = daybox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = startbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = instructorbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = roombox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = buildingbox == true ? totalOutPuts + 1 : totalOutPuts;
totalOutPuts = numberenrolled == true ? totalOutPuts + 1 : totalOutPuts;
int missingElements = 10 - totalOutPuts;

String groupBy = " Group by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10";
if (missingElements == 9) {
    groupBy = " Group by 1";
} else if (missingElements == 8) {
    groupBy = " Group by 1, 2";
} else if (missingElements == 7) {
    groupBy = " Group by 1, 2, 3";
} else if (missingElements == 6) {
    groupBy = " Group by 1, 2, 3, 4";
} else if (missingElements == 5) {
    groupBy = " Group by 1, 2, 3, 4, 5";
} else if (missingElements == 4) {
    groupBy = " Group by 1, 2, 3, 4, 5, 6";
} else if (missingElements == 3) {
    groupBy = " Group by 1, 2, 3, 4, 5, 6, 7";
} else if (missingElements == 2) {
    groupBy = " Group by 1, 2, 3, 4, 5, 6, 7, 8";
} else if (missingElements == 1) {
    groupBy = " Group by 1, 2, 3, 4, 5, 6, 7, 8, 9";
}

Answer 1

循环！这是一个实施建议：

// adding all the vars to an array might improve readability
boolean checks[] = new boolean[] { endbox, coursebox, departmentbox, callbox,
                                   daybox, startbox, instructorbox, roombox,
                                   buildingbox, numberenrolled };

for (boolean check : checks) {
    if (check) {
        totalOutPuts++;
    }
}

String groupBy = " Group by ";

// this isn't the best way of appending strings in Java,
// you'd be better using StringBuilder. this is for the sake of simplicity
for (int i = 1; i < totalOutPuts; i++) {
    groupBy += i + ", ";
}

// append the last number
groupBy += totalOutPuts + "";

Answer 2

首先要突出的是：

totalOutPuts = endbox == true ? totalOutPuts + 1 : totalOutPuts;

将布尔值与true进行比较是没有意义的，因为它已经是一个布尔值，只需这样做：

totalOutPuts = endbox ? totalOutPuts + 1 : totalOutPuts;

除此之外，您可以进一步简化为：

totalOutPuts += endbox ? 1 : 0; // same as totalOutPuts = totalOutPuts + (endbox ? 1 : 0);

或者，更具可读性：

if(endbox) {
    totalOutPuts += 1; // or ++totalOutPuts if you're into that sort of thing
}

然后在底部，你这样做：

int missingElements = 10 - totalOutPuts;

那么为什么不首先这样做呢？

int missingElements = 10;
if(endbox) {
    missingElements -= 1; // this means missingElements = missingElements - 1;
}
// etc

我做得对吗？

2 个答案: