問題描述

我想在哈希圖中添加相同鍵的值.例如:

I want to add the values of the same keys in a hashmap. For example:

   ABC --> 123  
   DEF --> 456  
   ABC --> 123  
   XXX --> 111  
   XXX --> 222

應該變成:

   ABC --> 246  
   DEF --> 456  
   XXX --> 333  

這是我目前的代碼:

public class Reading {


@SuppressWarnings("unchecked")
public static void main(String[] args) throws IOException {
    //Create hashmap to store the the string and int in the excel sheet
    HashMap<String, Integer> hm = new HashMap<String, Integer>();

    String key = null;
    int value = Integer.MIN_VALUE;
    // String chkeq; // this

    @SuppressWarnings("rawtypes")
    ArrayList list = new ArrayList();

    // File path or EXCEL file
    FileInputStream fos = new FileInputStream(
            "/Users/SG/Desktop/tester.xls");

    // Sheet is the individual sheet that the data is coming from, in this
    // case Sheet1

    try {

        // Put the XLS file into
        HSSFWorkbook workbook = new HSSFWorkbook(fos);

        // Get first sheet from the project
        HSSFSheet sheet = workbook.getSheetAt(0);

        // Go through each row
        Iterator<Row> rowIterator = sheet.iterator();
        while (rowIterator.hasNext()) {


            Row row = rowIterator.next();

            // Go through each column in the rows
            Iterator<Cell> cellIterator = row.cellIterator();
            while (cellIterator.hasNext()) {

                Cell cell = cellIterator.next();

                switch (cell.getCellType()) {
                    case Cell.CELL_TYPE_BOOLEAN:
                        //System.out.print(cell.getBooleanCellValue() + "		");

                        list.add(cell.getBooleanCellValue());
                        break;
                    case Cell.CELL_TYPE_NUMERIC:
                        //System.out.print(cell.getNumericCellValue() + "		");

                        value = (int) cell.getNumericCellValue();
                        list.add(cell.getNumericCellValue());
                        break;
                    case Cell.CELL_TYPE_STRING:
                        //System.out.print(cell.getStringCellValue() + "		");
                        key = cell.getStringCellValue();
                        //chkeq = cell.getStringCellValue();

                       /* for (int i = 0; cellIterator.hasNext(); i++) {
                            if (chkeq == cellIterator.next().getStringCellValue()) {
                                System.out.println("same" + cell.getStringCellValue());

                            }

                        }*/

                        list.add(cell.getStringCellValue());
                        break;
                }

                if (key != null && value != Integer.MIN_VALUE) {
                    hm.put(key, value);
                    key = null;
                    value = Integer.MIN_VALUE;
                }

            }
            //System.out.println("");

        }
        for (String keys : hm.keySet())
            System.out.println(keys + ":" + hm.get(keys));
        fos.close();
        // System.out.println(list);

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}
}

注意:我使用 Apache POI 從 Excel 工作表中提取數據.

Note: I have used Apache POI to extract the data from an Excel sheet.

代碼輸出如下:

DEF --> 456
ABC --> 123
XXX --> 222

所有這一切都是用相等的鍵覆蓋放入哈希圖中的最后一個單元格.

All this is doing is overwriting the last cell that was put into the hashmap with equal key.

有什么方法可以對這些值求和而不是覆蓋它們?

Is there any way to sum the values instead of writing over them?

推薦答案

Put 會覆蓋地圖中的任何內容.

Put overwrites whatever is in the map.

您需要獲取映射中鍵的當前值(如果存在)并將其添加到您要存儲的值中.

You need to get the current value in the map for the key (if it exists) and add it to the value you want to store.

if(hm.containsKey(key))
    hm.put(key, value + hm.get(key));
else
    hm.put(key, value);

這篇關于如何將與哈希圖中重復出現的鍵關聯的值相加的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！