two dimensional array horizontal average output

Question

I am stuck with a problem and i don\'t know how to put this in a for loop. I need the hotizontal average of the next matrix:

1 2 3 4 5

5 4 3 2 1

3 2 1 4 5


        

Answer 1

Do this in the language you want. Either Java, or Javascript. Pick one.

for (int i = 0; i < rows; ++i)
{
   double sum = 0;
   for (int j = 0; j < columns; ++j)
   {
      sum = sum + matrix[i][j];
   }
   double avg = sum / columns;
   print(avg);
}

Basically, this is: for each row in the matrix, create a sum of all elements, and then divide the sum by the number of columns to find the average of the row.

Answer 2

You can do like follows in javascript :

Have a div like

<div id="matrix_output"> </div>

and add the javascript code :

var dArray = [[1, 2, 3, 4, 5], [5, 4, 3, 2, 1], [3, 2, 1, 4, 5]];
 var texts='';
    for (i=0; i<dArray.length; i++)
    {
        sum=0;        
        for(j=0;j<dArray[i].length;j++){
          sum=sum+dArray[i][j];  
          texts=texts + dArray[i][j] + " \t";  
        }
        avg=sum/dArray[i].length;
        texts= texts + avg + " <br/>" ;
       dArray[i][dArray[i].length]=avg;

    }
 document.getElementById("matrix_output").innerHTML=texts;

Check the below link for reference :

http://jsfiddle.net/xGZPL/

Answer 3

Use map and reduce.

var matrix = [[1, 2, 3, 4, 5],[5, 4, 3, 2, 1],[3, 2, 1, 4, 5]]
var result = matrix.map(row=>row.reduce((a,b) => a+b)/row.length);
console.log(result.join(', '));

Answer 4

This piece of code alerts the data structured in a table-like string.

var dArray = [[1, 2, 3, 4, 5], [5, 4, 3, 2, 1], [3, 2, 1, 4, 5]];

var str = '';
dArray.forEach(function(arr, index){ 
  var average = arr.reduce(function(sum, item){ return sum + item; })/arr.length;
  str += '\n Array ' + index + ':  ' + arr.join(' ') + '   average: ' + average;
});
alert(str);

Answer 5

This will compute and place ur values in a new matrix with the average in the last column.

double[][] Table = new double[dArray.length][dArray[0].length+1];
double sum, avg;
for(int i = 0; i<dArray.length; i++)
{
    sum = 0;
    for(int j = 0; j<dArray[0].length; j++)
    {
        Table[i][j]=dArray[i][j];
        sum += dArray[i][j];
    }
    avg = sum/dArray[0].length;
    Table[i][dArray[0].length] = avg;
}

Answer 6

var res = [];
for(i = 0;i<dArray.length;i++){

var tot=0;
for(j=0;i<dArray[i].length;j++){

tot +=dArray[i][j];

}
res.push(tot/dArray[i].length);
}
return res;