Map<String, Object> objectMap3 = new HashMap<>(); objectMap3.put("name","c"); objectMap3.put("num",22); list.add(objectMap3); int sum = list.stream().filter(x-> "a".equals(x.get("name").toString()) || "b".equals(x.get("name").toString())).mapToInt(a->((int) ...
package test2;importjava.util.*;importjava.util.stream.Collectors;publicclassFenzu{publicstaticvoidmain(String[]args){Map<String,Object>map=newHashMap<String,Object>();map.put("name","a");map.put("price",500);Map<String,Object>map2=newHashMap<String,Object>();map2.put("name","a");...
Map<String, List<Map<String, Object>>> glist = list.stream().collect(Collectors.groupingBy(e -> e.get("projectCode").toString())); glist.forEach((k,slist)->{ Map<String,Object> nmap=new HashMap<>(); //这块是对某个key进行计算 可以求和 求平均值 求各种值 IntSummaryStatistics sumcc ...
使用Java merge对Map<String、Map<String、Integer>>中的数字求和 在Java8中使用stream收集List<Object>到Map<String、List<Object>> 使用Stream API创建对列表元素进行排序的Map<String、List<Object>> Java Jackson,使用Map<String编组类,不访问类代码库的Object> ...
Map<String, Object> map5 = new HashMap<>(); map5.put("userId", "159"); map5.put("value", 2022); list.add(map5); System.out.println("统计后的数据--->>>"+list); //根据userId key 合计value Map<String, Map<String, Object>> result = new HashMap<>(); ...
Map<String,Object> nmap=new HashMap<>(); IntSummaryStatistics sumcc = slist.stream().collect(Collectors. summarizingInt(e->Integer.valueOf(e.get("countorder").toString())); nmap.put("name", slist.get(0).get(name)); nmap.put("value", sumcc.getSum());//求和 datas...
public static double SumList(List<object> list) { double sum = 0; foreach (var item in list) { if (item is double || item is int || item is float) { sum += Convert.ToDouble(item); } } return sum; } 在这个示例代码中,我们假设只有数字类型的元素需要求和。如果还有其他需要考虑的类...
1.9 List<Map<String, Object>>转Map<String, List<Map<String, Object>>> Map<String, List<Map<String, Object>>> groupByGenderMap = pigMapList.stream().collect(groupingBy(e -> e.get("gender").toString())); 1.10 List求和、求最大值、平均值 ...
Map<String,Object> stu4 =newHashMap<String, Object>(); stu4.put("name", "卫庄"); stu4.put("score",newBigDecimal(30)); list.add(stu4); list= list.stream().collect(Collectors.groupingBy(d -> d.get("name"))).values().stream().map(d ->{ ...