Question

如何查找地图的键数的最大值

[在此处输入图片描述] 2

Answer 1

也许您可以使用Comparator并创建升序值数组列表

public static ArrayList<ObjectA> getObjectAList() {

    ArrayList<ObjectA> objectAList = new ArrayList<>();
    Collections.sort(objectAList, ObjectA.objectAValue);

    return objectAList;
}
public class ObjectA{
/* Comparator for sorting the list by value */
public static Comparator<ObjectA> objectAValue = new Comparator<ObjectA>() {

    @Override
    public int compare(ObjectA object1, ObjectA object2) {

        float value1 = object1.getValue();
        float value2 = object2.getValue();

        /* For ascending order */
        return Float.floatToIntBits(value1)-Float.floatToIntBits(value2);

    }
};

}

Answer 2

您可以执行以下操作：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class Main {
    public static void main(String[] args) {
        List<Map<String, Float>> elements = new ArrayList<Map<String, Float>>();

        Map<String, Float> element = new HashMap<String, Float>();
        element.put("a", (float) 1.22);
        element.put("b", (float) 1.33);
        element.put("c", (float) 1.52);
        element.put("d", (float) 1.352);
        element.put("e", (float) 1.452);
        element.put("f", (float) 1.42);

        Map<String, Float> element1 = new HashMap<String, Float>();
        element1.put("a", (float) 1.22);
        element1.put("b", (float) 1.32);
        element1.put("c", (float) 1.52);
        element1.put("d", (float) 1.32);
        element1.put("e", (float) 1.5552);
        element1.put("f", (float) 1.42);

        Map<String, Float> element2 = new HashMap<String, Float>();
        element2.put("a", (float) 1.22);
        element2.put("b", (float) 1.242);
        element2.put("c", (float) 1.552);
        element2.put("d", (float) 1.32);
        element2.put("e", (float) 1.542);
        element2.put("f", (float) 1.42);

        elements.add(element);
        elements.add(element1);
        elements.add(element2);

        System.out.println("Initial Mappings are: " + elements);

        String[] keys = { "a", "b", "c", "d", "e", "f" };
        List<Map<String, Float>> resultList = new ArrayList<Map<String, Float>>();
        Map<String, Float> resultMap;
        float min, max;
        for (int j = 0; j < keys.length; j++) {
            resultMap = new LinkedHashMap<String, Float>();
            max = elements.get(0).get(keys[j]);
            min = elements.get(0).get(keys[j]);
            for (int i = 1; i < elements.size(); i++) {
                if (max < elements.get(i).get(keys[j])) {
                    max = elements.get(i).get(keys[j]);
                }
                if (min > elements.get(i).get(keys[j])) {
                    min = elements.get(i).get(keys[j]);
                }
            }
            resultMap.put(keys[j] + "->min", min);
            resultMap.put("max", max);
            resultList.add(resultMap);
        }

        System.out.println("Result: " + resultList);
    }
}

输出：

Initial Mappings are: [{a=1.22, b=1.33, c=1.52, d=1.352, e=1.452, f=1.42}, {a=1.22, b=1.32, c=1.52, d=1.32, e=1.5552, f=1.42}, {a=1.22, b=1.242, c=1.552, d=1.32, e=1.542, f=1.42}]
Result: [{a->min=1.22, max=1.22}, {b->min=1.242, max=1.33}, {c->min=1.52, max=1.552}, {d->min=1.32, max=1.352}, {e->min=1.452, max=1.5552}, {f->min=1.42, max=1.42}]

如何计算Map <Strib，float>的Min Max

2 个答案: