# Find the mean vector of a Matrix

• Difficulty Level : Basic
• Last Updated : 19 Aug, 2022

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 .

Implementation:

## C++

 `// C++ program to find mean vector``// of given matrix``#include ``using` `namespace` `std;``#define rows 3``#define cols 3` `// Function to find mean vector``void` `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 code``int` `main()``{` `    ``int` `mat[rows][cols] = { { 1, 2, 3 },``                            ``{ 4, 5, 6 },``                            ``{ 7, 8, 9 } };` `    ``meanVector(mat);` `    ``return` `0;``}`

## Java

 `// Java program to find``// mean vector of given matrix``import` `java.io.*;` `class` `GFG``{``static` `int` `rows = ``3``;``static` `int` `cols = ``3``;` `// Function to``// find mean vector``static` `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 code``public` `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

 `# Python3 program to find``# mean vector of given``# matrix``rows ``=` `3``;``cols ``=` `3``;` `# Function to``# find mean vector``def` `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 Code``mat ``=` `[[``1``, ``2``, ``3``],``       ``[``4``, ``5``, ``6``],``       ``[``7``, ``8``, ``9``]];` `meanVector(mat);` `# This code is contributed``# by mits`

## C#

 `// C# program to find``// mean vector of given matrix``using` `System;` `class` `GFG``{``static` `int` `rows = 3;``static` `int` `cols = 3;` `// Function to``// find mean vector``static` `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 code``public` `static` `void` `Main ()``{``    ``int``[,] mat = {{1, 2, 3},``                  ``{4, 5, 6},``                  ``{7, 8, 9}};` `    ``meanVector(mat);``}``}` `// This code is contributed``// by anuj_67.`

## PHP

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## Javascript

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Output

`[ 4 5 6 ]`

Time Complexity: O(rows * cols)

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