java - 如何循环遍历数组来查找参数是否与数组中的元素匹配？

Question

String[] arr = new String[3];
public static void main(String args[]){
        classname n = new classname();
        arr[0] = "bob";
        arr[1] = "Lisa";
        arr[2] = "Rob";
        n.applesEaten(bob,5)
        n.applesEaten(bob,9)
        n.applesEaten(bob,5)
        n.applesEaten(Lisa,3)
        n.applesEaten(Lisa,5)
        n.applesEaten(Rob,7)
}
public int applesEaten(String name, int apples){
        //because this method was called 3 times for bob and bob ate 5+9+5 apples,
//this method should return 19. and 8 for Lisa, 7 for Rob.
}

我尝试使用单个 for 循环遍历 arr 数组，但是，循环添加了每个人的苹果，如何才能使该方法可以为不同名称返回不同数量的苹果？

Answer 1

您需要一个映射而不是数组，如下所示:

private static Map<String,Integer> arr = new HashMap<>(  );

public static void main(String args[]){

    applesEaten("bob",5);
    applesEaten("bob",9);
    applesEaten("bob",5);
    applesEaten("Lisa",3);
    applesEaten("Lisa",5);
    applesEaten("Rob",7);
}
public static int applesEaten(String name, int apples)
{
    return arr.compute(name, (k,v) -> (v == null) ? apples : v+apples );
}

根据要求，仅使用数组解决方案[但不要这样做:)]:

private static String[] arr = new String[3];

public static void main(String args[])
{
    arr[0] = "bob";
    arr[1] = "Lisa";
    arr[2] = "Rob";
    applesEaten("bob",5);
    applesEaten("bob",9);
    applesEaten("bob",5);
    applesEaten("Lisa",3);
    applesEaten("Lisa",5);
    applesEaten("Rob",7);
}
public static int applesEaten(String name, int apples)
{

    for ( int i = 0; i < arr.length; i++ )
    {
        String[] split = arr[i].split( "-" );
        if(split[0].equals( name ))
        {
            if(split.length==1)
            {
                arr[i]=name+"-"+apples;
                return apples;
            }
            else
            {
                int newApples = (Integer.parseInt( split[1] )+apples);
                arr[i]=name+"-"+newApples;
                return newApples;
            }

        }
    }
    return 0;
}