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Home  >  Article  >  Web Front-end  >  How to find the sum of all elements of a given array in JavaScript?

How to find the sum of all elements of a given array in JavaScript?

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2023-08-24 14:25:151922browse

如何在 JavaScript 中求给定数组所有元素的总和？

In programming, it is often necessary to find the sum of all elements in an array. have There are many ways to do this in JavaScript. In this tutorial we will learn about some Method to find the sum of all elements in an array.

Use for loop

Finding the sum of all elements in an array is a very common operation in JavaScript, for loop is the simplest method. If you are using arrays in JavaScript, be sure to utilize a for loop to find the sum of all elements in the array.

In JavaScript, a for loop is a control flow statement that allows you to iterate over a Given an array, object or string. The for loop will execute a set of statements for each element In an array, object or string. In this tutorial we will discuss the benefits of summation Use a for loop to count all elements of a given array.

One of the benefits of using a for loop to find the sum of all elements in an array is Very easy to code. You just create a variable to store the sum and then use The for loop iterates through the array, adding each element to the sum. This is a very concise Method to find the sum of an array.

Example 1

Below is the complete program to sum all elements in an array using for loop -

<!doctype html>
<html>
<head>
   <title>Examples</title>
</head>
<body>
   <h2> Finding sum of all elements using <i>for</i> loop: </h2>
   <div id="array"></div>
   <div id="result"></div>
   <script>
      const data = [2,4,6,8];
      let sum = 0;
      const len = data.length
      for (let i = 0; i < len; i++) {
         sum += data[i];
      }
      document.getElementById("array").innerHTML = "Array = [" + data+ "]";
      document.getElementById("result").innerHTML ="Sum of All Elements: " + sum;
   </script>
</body>
</html>

Output

The code will give the following output . 

Finding sum of all elements using for loop:
Array = [2,4,6,8]
Sum of All Elements: 20

There are some disadvantages to using a for loop in JavaScript to find the sum of all elements of a given array. They are as follows -

  • This is a time consuming process: Find the sum of all elements of an array using for Looping is a time-consuming process. This is because the loop must iterate Find the sum of all elements in an array.

  • This is a process that consumes memory: this is because, in order to find the sum of all elements elements of an array, all elements must first be stored in memory Then perform the process of finding their sum. This consumes a lot of memory.

  • This is a processor-intensive process: this is because the loop must iterate Find the sum of all elements of an array.

Use the reduce() method

To find the sum of all elements of an array, you can use the reduce() method. This method applies a function to each element in the array from left to right and returns a value.

reduce() The method takes two parameters: a function and an optional initial value. The function is executed for each element in the array and the return value is used as the new value for the next element in the array. The initial value is optional; if omitted, the first element in the array is used as the initial value.

If the array is empty, or an initial value is specified and the array has only one element, Return the initial value.

Example 2

The following example is implemented using the reduce() method -

<!doctype html>
<html>
<head>
   <title>Examples</title>
</head>
<body>
   <h2> Finding sum of all elements using <i>reduce()</i> method: </h2>
   <div id="array"></div>
   <div id="result"></div>
<script>
   var arr = [2, 4, 6, 8];
   var sum = arr.reduce(function(a,b){
      return a+b;
   }, 0);
   document.getElementById("array").innerHTML = "Array: " + arr;
   document.getElementById("result").innerHTML = "Sum of all elements in the array = " + sum;
</script>
</body>
</html>

Output

The code will give the following output. 

20Finding sum of all elements using reduce() method:
Array: 2,4,6,8
Sum of all elements in the array = 20

There are many advantages to using the reduce() method to find the sum of all elements. in an array. First, it is simple and concise. Secondly, it is easy to read and understand. third, It's efficient and fast. Finally, it can be used to sum any type of data, not just number.

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