Workspace, Variables, and Functions in MATLAB

Workspace

  • The workspace contains all variables we create while working in MATLAB.
  • Whenever we assign a value to a variable, it automatically gets space in the workspace.
  • Workspace variables lose their existence after the closing of the environment, so save these variables in a file to use later on.
  • We can import variables into MATLAB from data files.
  • We can import variables into MATLAB from other programs also.
  • The assignment operator (=) facilitates the creation of variables.
  • To access the variable from the workspace, we need to enter its name at the command line.
  • To view all available variables in the workspace, enter the command- 'whos' at the command line.
Workspace, Variables, and Functions in MATLAB

Workspace Pane in MATLAB

  • It is an area in the MATLAB environment with the name Workspace written on its top bar.
  • All variables currently being used or in the workspace, are displayed here.
  • Workspace pane can be maximized or minimized as per requirement.
  • We can add or remove the fields of the contents, which describe variables.
Workspace, Variables, and Functions in MATLAB

MAT-file in MATLAB

  • The file saved with .mat extension is called a MAT-file in MATLAB.
  • As variables in the workspace no longer exist after the closing of the environment, so these variables are saved in MAT-file for later use.
  • Use save command to save workspace contents in a file.
  • Ensure the file name is different from the previous file. Otherwise, it will overwrite the last existing file with the new one.
  • It saves the current workspace in the current working folder and a compressed file.

Current Folder Pane

Workspace, Variables, and Functions in MATLAB
  • We can change the current working folder by using the Browse For Folder button located above the current folder pane.
  • After running the save command, the file saved with .mat extension becomes visible in the Current Folder Pane.
  • After saving the workspace, we can clear all the contents of the workspace by using the clear command at the command line.
  • Syntax of the save command:
Workspace, Variables, and Functions in MATLAB

Using .mat files

  • Any .mat file can be included in the current workspace.
  • Use command load followed by filename with extension.
  • Syntax:
Workspace, Variables, and Functions in MATLAB
  • Before loading the file, ensure the parent folder is selected as the current folder; otherwise, it will show error:
Workspace, Variables, and Functions in MATLAB

Workspace after saving the file, clearing the content of the workspace, and before loading of the file:

Workspace, Variables, and Functions in MATLAB

Workspace after loading of the file, now we can use variables inside that file:

Workspace, Variables, and Functions in MATLAB

Text and Characters in MATLAB

Text in String Arrays

  • When text is enclosed in double quotes (" "), its data type or class is declared as String.
  • Strings are also arrays, like all other MATLAB variables.
  • Syntax:
Workspace, Variables, and Functions in MATLAB

Double quotes inside double quotes

  • When the text of the String itself includes double quotes, then use double quotes within the text, as:
Workspace, Variables, and Functions in MATLAB

Using whos command to View a single variable

  • As 'whos' command shows all variables within the workspace, we can use 'whos variable_name' command to view only the particular variable.
Workspace, Variables, and Functions in MATLAB

Concatenation of String using plus (+) operator

  • We can combine the value of other variables into a String.
Workspace, Variables, and Functions in MATLAB

Find the length of the String array in MATLAB

  • We can find the length of a string by using the strlength function.
Workspace, Variables, and Functions in MATLAB

String array with multiple elements

  • String array can also have multiple elements like number arrays.
Workspace, Variables, and Functions in MATLAB

Find the length of String array with multiple elements

  • The same strlength function is used to find the length.
  • It will display length in an array format with length calculated as an individual element.
Workspace, Variables, and Functions in MATLAB

Character Arrays in MATLAB

  • We use character array to store data that is not meaningful, or we can say that it doesn't resemble a text, such as a key or a password sequence, a DNA sequence.
  • Character array has a char data type.
  • Character array is declared in single quotes (' ').
Workspace, Variables, and Functions in MATLAB

Find a single character in character array

  • In character array, each character is stored as a separate element.
  • To find the character of an element, use the index number of that element in parenthesis with the variable.
Workspace, Variables, and Functions in MATLAB

Concatenation of Character Array in MATLAB

  • As we concatenate numeric arrays, here also use square brackets to concatenate character arrays.
Workspace, Variables, and Functions in MATLAB

Calling Functions in MATLAB

  • In MATLAB, a large number of functions are available that perform computational tasks.
  • These functions are the same as subroutines or methods in other programming languages.
  • Functions are called providing input arguments in its parenthesis.
  • Example:
    • function-name....max()
    • use.....finds the largest value in the array.
Workspace, Variables, and Functions in MATLAB
  • If it is a matrix, it will find the maximum value column-wise.
Workspace, Variables, and Functions in MATLAB
  • Use a comma to separate multiple input arguments.
  • Passing multiple arguments requires to agree on the matrix dimensions, as per calculation.
Workspace, Variables, and Functions in MATLAB

disp function in MATLAB

  • Used to display the input data as it is.
  • It doesn't store the output to the default ans variable.
  • Inputs for the function are provided in parenthesis.
Workspace, Variables, and Functions in MATLAB

clc function in MATLAB

  • It clears the command window by erasing all commands and outputs.
  • But previously entered commands can be accessed by using keyboard array keys on the command line.
  • It doesn't take any input, so it doesn't output anything.
Workspace, Variables, and Functions in MATLAB