Find the mean vector of a Matrix

13 Apr, 2021
Given a matrix of size M x N, the task is to find the Mean Vector of the given matrix. Examples:  
Input : mat[][] = {{1, 2, 3},
                   {4, 5, 6},
                   {7, 8, 9}}       
Output : Mean Vector is [4 5 6]
Mean of column 1 is (1 + 4 + 7) / 3 = 4
Mean of column 2 is (2 + 5 + 8) / 3 = 5
Mean of column 3 is (3 + 6 + 9) / 3 = 6

Input : mat[][] =  {{2, 4},
                    {6, 8}}
Output : Mean Vector is [4 6]
Mean of column 1 is (2 + 6) / 2 = 4
Mean of column 2 is (4 + 8) / 2 = 6
Approach: Lets take a matrix mat of dimension 5×3 representing lengths, breadths, heights of 5 objects. Now, the resulting mean vector will be a row vector of the following format :  
[mean(length) mean(breadth)  mean(height)]
Note: If we have a matrix of dimension M x N, then the resulting row vector will be having dimension 1 x N Now, simply calculate the mean of each column of the matrix which will give the required mean vector . 
C++
Java
Python3
C#
PHP
Javascript
// C++ program to find mean vector// of given matrix#include <bits/stdc++.h>using namespace std;#define rows 3#define cols 3 // Function to find mean vectorvoid meanVector(int mat[rows][cols]){    cout << "[ ";     // loop to traverse each column    for (int i = 0; i < rows; i++) {         // to calculate mean of each row        double mean = 0.00;         // to store sum of elements of a column        int sum = 0;         for (int j = 0; j < cols; j++)            sum += mat[j][i];         mean = sum / rows;        cout << mean << " ";    }     cout << "]";} // Drivers codeint main(){     int mat[rows][cols] = { { 1, 2, 3 },                            { 4, 5, 6 },                            { 7, 8, 9 } };     meanVector(mat);     return 0;}
// Java program to find// mean vector of given matriximport java.io.*; class GFG{static int rows = 3;static int cols = 3; // Function to// find mean vectorstatic void meanVector(int mat[][]){    System.out.print("[ ");     // loop to traverse    // each column    for (int i = 0; i < rows; i++)    {         // to calculate mean        // of each row        double mean = 0.00;         // to store sum of        // elements of a column        int sum = 0;         for (int j = 0; j < cols; j++)            sum += mat[j][i];         mean = sum / rows;        System.out.print((int)mean + " ");    }     System.out.print("]");} // Driver codepublic static void main (String[] args){    int mat[][] = {{1, 2, 3},                   {4, 5, 6},                   {7, 8, 9}};     meanVector(mat);}} // This code is contributed// by anuj_67.
# Python3 program to find# mean vector of given# matrixrows = 3;cols = 3; # Function to# find mean vectordef meanVector(mat):    print("[ ", end = "");     # loop to traverse    # each column    for i in range(rows):                 # to calculate        # mean of each row        mean = 0.00;         # to store sum of        # elements of a column        sum = 0;         for j in range(cols):            sum = sum + mat[j][i];         mean = int(sum /rows);        print(mean, end = " ");     print("]"); # Driver Codemat = [[1, 2, 3],       [4, 5, 6],       [7, 8, 9]]; meanVector(mat); # This code is contributed# by mits
// C# program to find// mean vector of given matrixusing System; class GFG{static int rows = 3;static int cols = 3; // Function to// find mean vectorstatic void meanVector(int [,]mat){    Console.Write("[ ");     // loop to traverse    // each column    for (int i = 0; i < rows; i++)    {         // to calculate mean        // of each row        double mean = 0.00;         // to store sum of        // elements of a column        int sum = 0;         for (int j = 0; j < cols; j++)            sum += mat[j, i];         mean = sum / rows;        Console.Write((int)mean + " ");    }     Console.Write("]");} // Driver codepublic static void Main (){    int[,] mat = {{1, 2, 3},                  {4, 5, 6},                  {7, 8, 9}};     meanVector(mat);}} // This code is contributed// by anuj_67.
<?php// PHP program to find mean// vector of given matrix$rows = 3;$cols = 3; // Function to find mean vectorfunction meanVector($mat){    global $rows ,$cols;    echo "[ ";     // loop to traverse    // each column    for ($i = 0; $i < $rows; $i++)    {         // to calculate        // mean of each row        $mean = 0.00;         // to store sum of        // elements of a column        $sum = 0;         for ($j = 0; $j < $cols; $j++)            $sum += $mat[$j][$i];         $mean = $sum /$rows;        echo $mean , " ";    }     echo "]";} // Driver Code$mat = array(array(1, 2, 3),             array(4, 5, 6),             array(7, 8, 9)); meanVector($mat); // This code is contributed// by anuj_6?>
<script> // Javascript program to find// mean vector of given matrixvar rows = 3;var cols = 3; // Function to find mean vectorfunction meanVector(mat){    document.write("[ ");     // Loop to traverse    // each column    for (var i = 0; i < rows; i++)    {                 // To calculate mean        // of each row        var mean = 0.00;         // to store sum of        // elements of a column        var sum = 0;         for (var j = 0; j < cols; j++)            sum += mat[j][i];         mean = sum / rows;        document.write(mean + " ");    }     document.write("]");} // Driver codevar mat = [ [ 1, 2, 3 ],            [ 4, 5, 6 ],            [ 7, 8, 9 ] ]; meanVector(mat);            // This code is contributed by Kirti </script>
[ 4 5 6 ]
 
Time Complexity: O(rows * cols) 
vt_m
Mithun Kumar
Kirti_Mangal
Mathematical
Matrix
Mathematical
Matrix
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