Accessing an element in an array on Matlab

I will be guiding you through the process of accessing a single element in a Matlab array.

To help illustrate this concept, I will provide you with a practical example.

Let's start by creating an array with four elements."

>> v=['a', 'b', 'c', 'd']

It is a one-dimensional array as it has only a single dimension.

Note that when the elements of an array are arranged in a single row or column, it is referred to as a one-dimensional or vector array. For instance: $$ v = \begin{pmatrix} a & b & c & d \end{pmatrix} $$ $$ v = \begin{pmatrix} a \\ b \\ c \\ d \end{pmatrix} $$

To access the first element of the array, simply type the name of the array followed by the position of the element in parentheses, such as v(1), and press enter.

>> v(1)
ans = a

Note. In Matlab the first element of an array is located at position one in the index. However, in programming languages such as Python or Java, the first element of an array is located at position zero in the index.

To access the second element of the array, simply type v(2).

>> v(2)
ans = b

To change the value of an element in the array, use the equal sign (=) followed by the value you want to assign to it.

For instance, to change the value of the second element, type v(2)='x'

>> v(2)='x'

Now, the vector v consists of the elements v=a, x, d, e.

>> v
ans = a, x, d, e

How can you access an element in a matrix?

A matrix is a 2D array consisting of rows and columns.

To retrieve a specific element, you need to specify both the row and column number (r,c).

For instance, let's consider a 2x2 matrix:

>> m=['a', 'b'; 'c', 'd']

In this case, the matrix is square, with two rows and two columns, and a total of four elements.

$$ \begin{pmatrix} a & b \\ c & d \end{pmatrix} $$

Note. When representing a matrix in Matlab, it's necessary to use 2D arrays. These arrays consist of two indices (r, c), with the first index indicating the row number (r) and the second index indicating the column number (c). To separate the two indices, simply use a comma.

To access a single element of an array, you can simply type the name of the array followed by the position of the element in parentheses, indicating its row and column.

For instance, to read the top-left element of a matrix, you would write m(1,1). This command retrieves the value of the element located in the first row and first column.

Here's an example:

>> m(1,1)
ans = a

To access the element on the first row and second column, you would type m(1,2).

>> m(1,2)
ans = b

If you want to read the second element on the second row, you can type m(2,2).

>> m(2,2)
ans = d