[英]Finding the mode of a 2D array
I'm trying to return the mode of a 2D array using a frequency array.我正在尝试使用频率数组返回二维数组的模式。 I have an array, score, which is of length 10, and has 3 columns.我有一个数组 score,长度为 10,有 3 列。 Each column contains an int that is between 0 and 100.每列包含一个介于 0 和 100 之间的 int。
I'm trying to find a way that will iterate through the array and return the modal value.我试图找到一种方法来遍历数组并返回模态值。 What I have so far is:到目前为止我所拥有的是:
int value = 0;
int[] freq = new int[100];
for (int row = 0; row < score.length; row++) {
for (int col = 0; col < score[row].length; col++) {
score[row][col] = value;
freq[value]++;
}
}
int largest = 0;
int mode = -1;
for (int i = 0; i < 100; i++) {
if (freq[i] > largest)
{
largest = freq[i];
mode = i;
}
}
System.out.println("modal score is: " +mode);
Problem is that this is just returning the modal score as 0, which it isn't.问题是这只是将模态分数返回为 0,而事实并非如此。
You have a problem on generating the freq
array.您在生成freq
数组时遇到问题。 If I understand correctly, on the first double-for block you are trying to put the frequencies of the numbers inside the freq
array.如果我理解正确,在第一个 double-for 块上,您试图将数字的freq
放入freq
数组中。
But all you do is:但你要做的就是:
int value = 0;
.....
score[row][col] = value;
freq[value]++;`
firstly you are changing the score
array,( which is a problem for you I guess...) and the you go to freq[0]
and do ++
.首先,您正在更改score
数组,(我猜这对您来说是个问题...)然后您转到freq[0]
并执行++
。 Obviously modal is 0, that number appears in all of the array.显然 modal 是 0,这个数字出现在所有的数组中。
SOLUTION: in the first double for block you should do:解决方案:在第一个 double for 块中,您应该执行以下操作:
value = score[row][col];
freq[value]++;
so I think you mixed up the order of the line, it should be the other way around.所以我认为你混淆了行的顺序,应该是相反的。
private static void printMode(double[][] doubles) {
HashMap<Double , Double> map = new HashMap();
for (int i = 0; i < doubles.length; i++) {
for (int j = 0; j < doubles[i].length; j++) {
double temp = doubles[i][j];
if(map.get(temp)==null){
map.put(doubles[i][j],1.0);
}else {
double temp2 = (double) map.get(temp);
map.put(doubles[i][j],++temp2);
}
}
}
Object[] objects = map.values().stream().sorted().toArray();
Stream stream = map.entrySet().stream().filter(val-> val.getValue().equals(objects[objects.length-1]));
stream.forEach(System.out::println);
}
I think using Stream for finding mode is the best way.我认为使用 Stream 查找模式是最好的方法。 use int instead of double doesn't cause any problems.使用 int 而不是 double 不会引起任何问题。
int value = 0;
int [] freq = new int [arr.length];
for (int i = 0; i < arr.length; i++){
for (int j = 0; j < arr[i].length; j++){
value = arr[i][j];
freq[value]++;
}
}
int largest = 0;
int mode = 0;
for (int i = 0; i < freq.length; i++) {
if (freq[i] > largest)
{
largest = freq[i];
mode = i;
}
}
System.out.println("modal score is: " +mode);
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