java 如何在二维数组JAVA中找到元素的平均值？
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How to find average of elements in 2d array JAVA?
提问by E. Hazard
I need help with the following program:
我需要以下程序的帮助：
"Write a method that will take a two-dimensional array of doubles as an input parameter & return the average of the elements of the array."
“编写一个方法，将二维数组作为输入参数并返回数组元素的平均值。”
Can anyone tell me how to go about it?
谁能告诉我该怎么做？
My current code:
我目前的代码：
public static double average(float arr[][]) {
double sum = 0;
int count = 0;
for (int row = 0; row < arr.length; row++)
for (int col = 0; col < arr[0].length; col++)
{
sum += arr[row][col];
count++;
}
return sum/count;
}
I don't know how to let the user input the array elements and array dimensions (row/columns). Also how do I call this method from main? I am getting errors.
我不知道如何让用户输入数组元素和数组维度（行/列）。另外我如何从main调用这个方法？我收到错误。
回答by user6904265
If you want to to all in one line (two-dimensional intarray):
如果你想在一行（二维int数组）：
Arrays.stream(array).flatMapToInt(Arrays::stream).average().getAsDouble();
If you deal with a two-dimensional doublearray:
如果你处理一个二维double数组：
Arrays.stream(array).flatMapToDouble(Arrays::stream).average().getAsDouble();
回答by Dani
try this:
试试这个：
Code:
代码：
public class AverageElements {
private static double[][] array;
public static void main (String[] args){
// Initialize array
initializeArray();
// Calculate average
System.out.println(getAverage());
}
private static void initializeArray(){
array = new double[5][2];
array[0][0]=1.1;
array[0][1]=12.3;
array[1][0]=3.4;
array[1][1]=5.8;
array[2][0]=9.8;
array[2][1]=5.7;
array[3][0]=4.6;
array[3][1]=7.45698;
array[4][0]=1.22;
array[4][1]=3.1478;
}
private static double getAverage(){
int counter=0;
double sum = 0;
for(int i=0;i<array.length;i++){
for(int j=0;j<array[i].length;j++){
sum = sum+array[i][j];
counter++;
}
}
return sum / counter;
}
}
Output:
输出：
5.452478000000001
回答by mincoder
Since you asked so nicely! Here is the code:
既然你问得这么好！这是代码：
public double Averagearray(double[][] array) {
double total=0;
int totallength;
for(int i=0;i<array.length;i++) {
for(int j=0;j<array[i].length;j++) {
total+=array[i][j];
totallength++;
}
}
return total/(totallength);
}
