How to Create and Add Variables in MATLAB

In MATLAB, the phrase "add variables" can refer to several actions, depending on the context. It might mean performing mathematical addition on the values stored in variables, creating new variables by assigning values, or even deriving a new variable from a selection within an existing one.

This guide explains these common interpretations and how to perform them in MATLAB.

Mathematical Addition of Variables

The most common way to "add variables" is to perform a mathematical sum of their values. This is done using the standard + operator.

% Example: Adding two scalar variables
variable1 = 10;
variable2 = 5;
sum_result = variable1 + variable2; % sum_result will be 15
disp(sum_result);

This also works for arrays, matrices, and vectors of compatible sizes:

% Example: Adding arrays (element-wise)
array1 = [1, 2, 3];
array2 = [4, 5, 6];
array_sum = array1 + array2; % array_sum will be [5, 7, 9]
disp(array_sum);

Creating New Variables (Assignment)

Another interpretation is simply "adding" a new variable to your workspace by assigning a value to a new variable name. This is done using the assignment operator (=).

% Example: Creating a new variable named 'myVariable'
myVariable = 100;
% Example: Creating a string variable
greeting = 'Hello, MATLAB!';

Once created, these variables appear in the MATLAB Workspace and can be used in calculations or further operations.

Deriving New Variables from Existing Data in the Variables Editor

MATLAB also allows you to create a new variable directly from a selection within an existing variable using the graphical user interface (GUI) in the Variables editor. This is useful for extracting subsets of data into a new variable.

According to the documentation: To create a new workspace variable from an existing variable, in the Variables editor, select an element, data range, row, or column in an array, and then in the Variable tab, select New from Selection.

Here are the steps based on this method:

1. Open the Variables Editor: Double-click a variable in the Workspace window to open it in the Variables editor.
2. Select Data: Inside the Variables editor, highlight the specific elements, a range of data, a row, or a column you want to turn into a new variable.
3. Use the Menu: Go to the Variable tab that appears when the Variables editor is active.
4. Create New Variable: Click the New from Selection button in the Variable tab.
5. Name and Save: A dialog box will appear allowing you to name the new variable before it is added to your workspace.

This method is distinct from mathematical addition but represents a way to "add" a new variable based on existing data using the GUI tools.

Summary of Variable Handling

Here's a quick look at the different ways "add variables" can be interpreted:

Understanding these different actions will help you effectively work with variables in MATLAB.