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This tutorial will discuss creating variables in Matlab and storing data in variables.

MATLAB variables

Variables are used to store data in Matlab. When we create a variable, Matlab allocates some memory for that variable to store the data.

If we store data in a variable, we can use the variable name instead of the data.

For example, if we want to multiply and add two numbers, we can save them in two variables, and then we can use their names to multiply and add.

See the code below.

clc
a = 100;
b = 50;
mul = a*b
add = a+b

Output:

mul =

        5000


add =

   150

If we use a semicolon after storing a value into a variable, Matlab will not display the value in the command window. In Matlab, we can write code in script files and in the command window.

The above code is written in a script file. In the output, you can see that only the variables muland addare displayed in the command window because they do not contain a semicolon at the end. You can also view the variables and their values ​​in the workspace window.

The command at the beginning of the code clcis used to clear the command window. We can use whosthe command to check the name, size, bytes, and class or data type of a variable.

For example, let us use the command in the above code whos. See the code below.

a = 100;
b = 50;
mul = a*b;
add = a+b;
whos

Output:

  Name      Size            Bytes  Class     Attributes

  a         1x1                 8  double              
  add       1x1                 8  double              
  b         1x1                 8  double              
  mul       1x1                 8  double    

In the output, all variables have the same size and category. clearVariables stored in the workspace remain there unless we close Matlab or clear them from the workspace using the command.

We can store data of various classes or data types in variables in Matlab such as characters using single quotes, strings using double quotes, cell arrays using curly brackets, vectors using square brackets, and matrices using square brackets.

Let us create variables with different data types. See the code below.

a = {1,2};
b = [1 2];
c = 'Char';
d = "String";
e = {'char',"string",5};
whos

Output:

  Name      Size            Bytes  Class     Attributes

  a         1x2               224  cell                
  b         1x2                16  double              
  c         1x4                 8  char                
  d         1x1               150  string              
  e         1x3               478  cell                

We can store different data types or class variables in cell arrays.

A variable name should start with a letter including numbers and underscores. It should not contain periods, arithmetic symbols, and spaces. If you want to write multiple strings in one variable name, you can separate them from each other using underscores.

If we pass the values ​​separated by spaces inside the square brackets, it will create a row vector. If we pass the values ​​separated by semicolons, Matlab will create a column vector.

In the same way, we can create a matrix in Matlab by writing values ​​separated by spaces to create a row, and then adding a semicolon to jump to the second row.

For example, let us create a row vector, column vector, and a matrix in Matlab. See the code below.

a = [1 2 5]
b = [1;2;5]
c = [1 2; 3 5]
whos

Output:

a =

     1     2     5


b =

     1
     2
     5


c =

     1     2
     3     5

  Name      Size            Bytes  Class     Attributes

  a         1x3                24  double              
  b         3x1                24  double              
  c         2x2                32  double              

You can check the size of a variable to know whether it is a row vector, column vector, or matrix.

Values ​​should be stored in variables before using them. If we do not assign expression values ​​to variables, Matlab will assign the values ​​to the variables and we can use them later.

There are many reserved keywords in Matlab that we cannot use as variable names. To check the reserved variables in Matlab, we can use iskeywordthe command which will list all the reserved keywords.

There are some predefined expressions in Matlab that we can use in our code like pi.

We can use the colon operator to create a large array of numbers. Creating an array of numbers takes a lot of time, like creating an array of integers from 1 to 100. In this case, we can use the colon operator to create the array instantly.

For example, let us create an array from 1 to 100. See the code below.

a = 0:1:100;
whos

Output:

  Name      Size             Bytes  Class     Attributes

  a         1x101              808  double              

To create an array, we have to write the initial value, incremental and final value separated by the colon operator.