Map<Object, AtomicInteger> 转换为关联数组

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英文:

Map<Object, AtomicInteger> to Associative array

问题

我有一个输入为int[]的数组,其内容如下:

[5, 65, 22, 1, 58, 5, 69, 12, 1, 22, 22, 58, 12, 54, 89]

使用Map&lt;Object, AtomicInteger&gt;,我将其转换为以下对象:

{1=2, 65=1, 5=2, 69=1, 22=3, 58=2, 12=1}

换句话说,我正在计算动态数组中重复的元素。

现在我需要找出最大和最小的重复次数,但我在进一步的步骤上陷入困境。

重复元素类的代码如下:

public Map&lt;Object, AtomicInteger&gt; countRepeatingElements(int[] inputArray) {
    ConcurrentMap&lt;Object, AtomicInteger&gt; output = 
                  new ConcurrentHashMap&lt;Object, AtomicInteger&gt;();

    for (Object i : inputArray) {
        output.putIfAbsent(i, new AtomicInteger(0));
        output.get(i).incrementAndGet();
    }

    return output;
}
英文:

I have for input int[] with the following content:

[5, 65, 22, 1, 58, 5, 69, 12, 1, 22, 22, 58, 12, 54, 89]

Using Map&lt;Object, AtomicInteger&gt;, I'm converting it to the following object:

{1=2, 65=1, 5=2, 69=1, 22=3, 58=2, 12=1}

In other words, I'm calculating the repeating elements of the dynamic array.

Now I need to find out the max and min occurrence and I'm really stuck on further steps.

The code of repeating elements class is below:

public Map&lt;Object, AtomicInteger&gt; countRepeatingElements(int[] inputArray) {
    ConcurrentMap&lt;Object, AtomicInteger&gt; output = 
                  new ConcurrentHashMap&lt;Object, AtomicInteger&gt;();

    for (Object i : inputArray) {
        output.putIfAbsent(i, new AtomicInteger(0));
        output.get(i).incrementAndGet();
    }

    return output;
}

答案1

得分: 2

如果你想找到最大和最小的出现次数,通过使用 EntrySet 遍历 Map,并比较每个键的值。

    int min = Integer.MAX_VALUE;
    int max = Integer.MIN_VALUE;
    for(Map.Entry<Object, AtomicInteger> entry : output.entrySet()){
        if(entry.getValue().intValue() < min){
            min = entry.getValue().intValue();
        }
        if(entry.getValue().intValue() > max){
            max = entry.getValue().intValue();
        }
    // entry.getValue() 可以获取数字出现的次数
    // entry.getKey() 可以获取数字本身
    }
英文:

If you want to find the max and the min occurrence, iterate through the Map using the EntrySet and compare the values of each key.

int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
for(Map.Entry&lt;Object, AtomicInteger&gt; entry : output.entrySet()){
    if(entry.getValue().intValue() &lt; min){
        min = entry.getValue().intValue();
    }
    if(entry.getValue().intValue() &gt; max){
        max = entry.getValue().intValue();
    }
// entry.getValue() gives you number of times number occurs
// entry.getKey() gives you the number itself
}

答案2

得分: 1

Sure, here's the translated code:

int[] inputArray = {5, 65, 22, 1, 58, 5, 69, 12, 1, 22, 22, 58, 12, 54, 89};

// 1
Map<Integer, Long> grouped = Arrays.stream(inputArray)
        .boxed()
        .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

// 2
LongSummaryStatistics stats = grouped.values()
        .stream()
        .mapToLong(Long::longValue)
        .summaryStatistics();

System.out.println(stats.getMax());
System.out.println(stats.getMin());
英文:
int[] inputArray = {5, 65, 22, 1, 58, 5, 69, 12, 1, 22, 22, 58, 12, 54, 89};

// 1
Map&lt;Integer, Long&gt; grouped = Arrays.stream(inputArray)
        .boxed()
        .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

// 2
LongSummaryStatistics stats = grouped.values()
        .stream()
        .mapToLong(Long::longValue)
        .summaryStatistics();

System.out.println(stats.getMax());
System.out.println(stats.getMin());

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  • 本文由 发表于 2020年4月10日 22:48:41
  • 转载请务必保留本文链接:https://go.coder-hub.com/61142793.html
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