Find the sum of rows of an array javascript

JavaScript is a programming language widely used in web development. It has a rich set of built-in functions and third-party libraries, making it ideal for processing various data structures. In this article, we will explore how to sum the rows of an array using JavaScript.

Array is a very important data structure in JavaScript. It can store multiple values ​​and access these values ​​through index. When working with arrays, sometimes you need to calculate the sum of the values ​​in each row. This article will introduce how to use JavaScript to achieve this function.

First, we need to create a two-dimensional array. For example, the following code creates a 3x3 two-dimensional array:

let arr = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

Now, we need to calculate the sum of each row. We can use a loop to iterate through each row in the array and then calculate the sum of that row on each iteration. The following is an example of using a for loop to calculate the sum of the rows of an array:

for (let i = 0; i < arr.length; i++) {
  let sum = 0;
  for (let j = 0; j < arr[i].length; j++) {
    sum += arr[i][j];
  }
  console.log(`Row ${i+1} Sum: ${sum}`);
}

In the above code, the outer for loop traverses each row of the array, and the inner for loop traverses each row in the current row. a value and add them to a sum variable. Then, we output the sum of the current row.

The output of this code looks like this:

Row 1 Sum: 6
Row 2 Sum: 15
Row 3 Sum: 24

We can also store the sum of each row in a new array so that we can use them more conveniently. Here is a sample code:

let rowSums = [];
for (let i = 0; i < arr.length; i++) {
  let sum = 0;
  for (let j = 0; j < arr[i].length; j++) {
    sum += arr[i][j];
  }
  rowSums.push(sum);
}
console.log(rowSums);

In the above code, we have created an empty array called rowSums and put the result into this array every time we calculate the sum of rows. Then, we output the contents of the rowSums array.

The output of this code looks like this:

[6, 15, 24]

We can also use the reduce function in JavaScript to calculate the sum of each row. The reduce function is used to combine all items in an array into a single value and accepts two parameters: a callback function and an optional initial value. Below is a sample code that uses the reduce function to calculate the sum of rows:

let rowSums = arr.map(row => row.reduce((acc, val) => acc + val));
console.log(rowSums);

In the above code, we use the map function to iterate through each row of the array and use the reduce function to accumulate all the values ​​in the row. This will generate a new array containing the sum of each row. Finally, we print the contents of the rowSums array.

The output of this code is the same as the previous example:

[6, 15, 24]

In JavaScript, there are multiple ways to calculate the sum of rows of a two-dimensional array. Using a for loop or reduce function are both good choices, depending on the specific application scenario and programming preferences. No matter which method you choose, iterating through a two-dimensional array and calculating the sum of each row is very simple and intuitive.

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