# Adding to an Array in Matlab

In this comprehensive guide, we will explore how to add to an array using the programming language Matlab. We’ll cover the fundamental concepts and different methods of adding elements to arrays in a …

Updated October 15, 2023

*Hey! If you love Computer Vision and AI, let's connect on Twitter or LinkedIn. I talk about this stuff all the time!*In this comprehensive guide, we will explore how to add to an array using the programming language Matlab. We’ll cover the fundamental concepts and different methods of adding elements to arrays in a step-by-step approach. To demonstrate these ideas effectively, we will also provide sample code snippets that showcase the application of each method. This article should be particularly helpful for those who are new to programming with Matlab or want to enhance their knowledge of its array manipulation techniques.

## Introduction to Arrays in Matlab

Before delving into the various methods for adding elements to an array, let’s first briefly discuss what arrays are and why they are essential components in a wide range of computational tasks. Arrays are fundamental data structures used in almost all programming languages that represent groups or collections of data organized sequentially in memory. In Matlab, arrays can be either vectors, matrices, or multi-dimensional arrays (higher dimensions than 2). These data types provide the necessary building blocks for various scientific and engineering computations since they enable efficient processing, manipulation, and analysis of data sets.

## Adding Elements to an Array

Now that we understand the significance of arrays in Matlab, let’s examine some methods for adding elements to these structures:

### 1. Horizontal Concatenation (Row-wise)

Horizontal concatenation, also known as “row-wise” or “column binding,” is one way to add new values to an array while maintaining the original dimension. This method is often used when appending multiple vectors into a single matrix or adding more columns to an existing matrix.

To perform horizontal concatenation in Matlab, we can use the function `[A B]`

, where A and B are two arrays that share a common dimension (usually rows). This operator combines the data from both matrices along their first dimension, forming a new array with the same number of rows as A or B but with more columns (their combined column count) if they have different numbers of columns.

#### Example:

Let’s demonstrate horizontal concatenation by creating two 1x3 matrices and then combining them into one 1x6 matrix.

```
A = [1 2 3];
B = [4 5 6];
C = [A B] % Add A and B horizontally to create a 1x6 matrix with columns (1, 2, 3, 4, 5, 6)
```

The output `C`

is: `[1 2 3 4 5 6]`

### 2. Vertical Concatenation (Column-wise)

Vertical concatenation, also known as “column-wise” or “row binding,” serves the same purpose as horizontal concatenation but instead involves joining two arrays along their second dimension. This method is frequently used when appending multiple matrices into a single array or adding more rows to an existing matrix.

To perform vertical concatenation in Matlab, we can utilize the `[A ; B]`

notation, where A and B are two arrays with the same number of columns (usually rows). This operator merges the data from both matrices into a new array, forming a larger matrix by keeping the shared column dimension while increasing its row count.

#### Example:

We will now demonstrate vertical concatenation by creating two 3x1 matrices and then combining them into one 5x1 matrix.

```
A = [1; 2; 3];
B = [4; 5; 6];
C = [A ; B] % Add A and B vertically to create a 5x1 matrix with rows (1, 2, 3, 4, 5)
```

The output `C`

is: `[1 2 3 4 5]`

### 3. Extending an Array using Appends

Sometimes we want to append a new value or vector to the end of an existing array without altering its original dimension. Matlab provides a dedicated function for this purpose called `append`

, which allows us to extend an array in various dimensions (rows, columns, or higher). The syntax for using `append`

involves supplying the desired input argument along with the target array as an input parameter.

#### Example:

We will demonstrate the use of `append`

by creating a 1x4 matrix and then adding two new values at the end to form a 1x6 matrix while keeping its row dimension unchanged.

```
A = [1 2 3 4];
B = append(A, [5; 6]); % Add values [5; 6] to A along its last dimension, keeping the original rows (1) and increasing columns (from 4 to 6).
```

The output `B`

is: `[1 2 3 4 5 6]`

## Conclusion

As we have seen in this article, Matlab offers various methods for adding elements to an array based on the desired result and intended data structure. From horizontal and vertical concatenation techniques to more advanced functions such as `append`

, it is crucial to understand these manipulations when working with arrays. We have provided sample code snippets that demonstrate each of these approaches, enabling you to incorporate them effectively into your programming workflows in Matlab. With this knowledge, you can now address array manipulation challenges more confidently and efficiently.