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文本文件包含用逗号分隔的数字（例如 458.58、1598.45...）。

我想将文本文件中的一整行添加到 ArrayList 中。

到目前为止，这是我的代码：

// to calculate final output
ArrayList<String> weeklySales = new ArrayList<String>(7);

// week 1 sales
while(file.hasNext()) {
    weeklySales.add(file.nextLine());
    System.out.println("I ran!");
}

System.out.println(weeklySales);

编辑：对不起，我的问题不清楚。我的问题是在运行此代码后，它将整个文本文件的所有元素添加到我的数组中，但我只需要将 1 行添加到它自己的单个 ArrayList 中。所以总的来说，我将拥有与文件中文本行一样多的数组列表。

4

2 回答 2

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这是代码，您可以使用：

String line = "458.58, 1598.45";
String array[] = line.split(", ");

可以通过这种方式从 String 更改为 double ：

Double.valueOf(array[i]);

可以通过以下方式将数组更改为列表：

ArrayList<String> list = new ArrayList<>();
list.addAll(Arrays.asList(array));
于 2013-10-12T22:05:12.310 回答
0

我终于让它工作了。我意识到处理单个行和从文本文件中分离单个数字的最方便的方法是使用 StringTokenizer。这是完整的工作代码，您只需要名为“SalesData.txt”的文本文件，我的包含以下 3 行：

1245.67,1490.07,1679.87,2371.46,1783.92,1461.99,2059.77 2541.36,2965.88,1965.32,1845.23,7021.11,9652.74,1469.36 2513.45,1963.22,1568.35,1966.35,1893.25,1025.36,1128.36

该程序输出以下内容： - 每周总销售额 -
每周日
平均值
- 所有周的
总
销售额 - 每周平均总销售额 - 销售额最高的一周 - 销售额
最低的一周

DecimalFormat formatter = new DecimalFormat("#0.00");

// create file object
File salesData = new File("SalesData.txt");

// open file
Scanner file  = new Scanner(salesData);

// declare 2 dimensional array 
double[][] weeklySales = new double[3][7];

// loop to initialize token
int row = 0;
while(file.hasNext()) {
// initialize token
String line = file.nextLine();
StringTokenizer tokens = new StringTokenizer(line, ",");

// fill columns and rows
int col = 0;
while(tokens.hasMoreTokens()) {
        // convert to double and assign to token
    weeklySales[row][col] = Double.parseDouble(tokens.nextToken());
    // move up 1 column
    col++;
    }
// move down 1 row
row++;
}

// calculate weekly sales
double week1Sales = 0, week2Sales = 0, week3Sales = 0;
for(int i = 0; i < 3; i++) {
    for(int j = 0; j < 5; j++) {
        double daily = weeklySales[i][j];
        if(i == 0)
            week1Sales += daily;
        else if(i == 1)
            week2Sales += daily;
        else if(i == 2)
            week3Sales += daily;
    }
}
// week 1 sales
System.out.println("Week 1 total sales: $" +formatter.format(week1Sales));
// week 2 sales
System.out.println("Week 1 total sales: $" +formatter.format(week2Sales));
// week 3 sales
System.out.println("Week 1 total sales: $" +formatter.format(week3Sales));

// average daily for week 1
System.out.println("Daily average for week 1: $" +formatter.format(week1Sales / 7));

// average daily for week 2
System.out.println("Daily average for week 2: $" +formatter.format(week2Sales / 7));

// average daily for week 3
System.out.println("Daily average for week 3: $" +formatter.format(week3Sales / 7));

// total for all weeks
double weeklyTotal = week1Sales + week2Sales + week3Sales;

System.out.println("Total sales of all the weeks: $" +formatter.format(weeklyTotal));

// average weekly sales
System.out.println("Average weekly total: $" + formatter.format(weeklyTotal / 3));

// week number with highest sales
if(week1Sales > week2Sales)
    if(week1Sales > week3Sales)
        System.out.println("The week with the highest sales is week 1.");
    else
        System.out.println("The week with the highest sales is week 3.");
else if(week2Sales > week3Sales)
    if(week2Sales > week1Sales)
        System.out.println("The week with the highest sales is week 2.");
    else
        System.out.println("The week with the highest sales is week 1.");
else
    System.out.println("The week with the highest sales is week 3.");

// week number with the lowest
if(!(week1Sales > week2Sales))
    if(!(week1Sales > week3Sales))
        System.out.println("The week with the lowest sales is week 1.");
    else
        System.out.println("The week with the lowest sales is week 3.");
else if(!(week2Sales > week3Sales))
    if(!(week2Sales > week1Sales))
        System.out.println("The week with the lowest sales is week 2.");
    else
        System.out.println("The week with the lowest sales is week 1.");
else
    System.out.println("The week with the lowest sales is week 3.");
于 2013-10-13T06:54:27.407 回答