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# How to compute the average of an array after mapping each element to a value in JavaScript ?

• Last Updated : 22 Jul, 2021

Given an array, the task is to compute the average of an array after mapping each element to a value.

```Input : arr=[2, 3, 5, 6, 7]
Output: 4.6
Explanation : (2+3+5+6+7)/5 = 4.6

Input : [5,7,2,7,8,3,9,3]
Output: 5.5
Explanation : (5+7+2+7+8+3+9+3)/8 = 5.5 ```

Approach1:

• Iterate the array elements using foreach() loop.
• Store the sum of each element in a variable.
• The average of all elements will be sum/length where length is the size of the given array.

Index.js

## Javascript

 ``

Output:

`4.6`

Approach 2:

• Iterate the  numbers of the array using for loop
• Use  ParseInt() function to parse the numbers in decimal format.
• Store the sum of numbers in a variable.
• The average of all elements will be sum/length where length is the size of the given array.

Index.js

## Javascript

 ``

Output:

` 4.6`

Approach 3: Using reduce() function

• In this approach, We reduce i.e replace two numbers of the array with their sum in the original array.
• reduce() function returns a single value i.e the sum of all the numbers of the array.
• Store the return value in a variable (sum variable used).
• The average of all elements will be sum/length where length is the size of the given array.

Index.js

## Javascript

 ``

Output:

`2.5`

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