Common MATLAB Commands
The following table contains a listing of commands that you use relatively often in MATLAB. You won’t find every command listed — that would require a book in itself. However, these commands are usually used several times each session.
| Command | Purpose |
cla |
Clears the current plot. |
Clc |
Clears the Command window |
clear <variable name> |
Removes a specific variable from the Workspace window (as specified by <variable name>). |
clear all |
Removes all of the variables from the Workspace window. |
close <figure name> |
Closes a specific figure (as specified by <figure name>). |
close all |
Closes all the current figures. |
diary <filename> |
Specifies the name of the file to use for the Diary feature. |
diary off |
Stops saving the Command window text to a file. |
diary on |
Starts saving the Command window text to a file. |
exist <keyword> |
Checks whether a keyword or file is in use. |
figure(<number>) |
Obtains the handle for the specified figure. |
findobj('Type', 'figure') |
Obtains the handles for all existing figures. |
format compact |
Removes extraneous spaces from the Command Window. Use the loose option to restore the default display. Other options include: short (default), long, short e, long e, short g, long g, short eng, and long eng. |
gca |
Obtains a handle to the current axes. |
gcf |
Obtains a handle to the current figure. |
gco |
Obtains a handle to the current object. |
get(<handle>, <property>) |
Obtains the <property> found in the object pointed at by <handle>. |
help <command or file> |
Displays help documentation for the <command> or comments in files you’ve created. |
iskeyword |
Displays a list of all the MATLAB keywords. |
iskeyword <name> |
Determines whether <name> is a keyword. |
load <filename> |
Loads the file containing variables to the Workspace window. |
more off |
Displays output using standard scrolling so that all the output appears simultaneously. |
more on |
Tells MATLAB to display output one screen at a time. |
save <filename> |
Saves the variables shown in the Workspace window to the specified file. |
set(<handle>, <property>, <value>) |
Sets the <property> found in the object pointed at by <handle> to the specified <value>. |
MATLAB Common Operator Summary
It’s important to know which operators MATLAB supports, and remembering them all isn’t always easy. The following table provides a quick summary of the operators that MATLAB supports.
| Operator | Type | Description | Example |
– |
Arithmetic | Subtracts the right operand from left operand | 5 — 2 = 3 |
* |
Arithmetic | Multiplies the right operand by the left operand | 5 * 2 = 10 |
^ |
Arithmetic | Calculates the exponential value of the right operand raised to the power of the left operand | 5^2 = 25 |
/ |
Arithmetic | Divides the left operand by the right operand | 5 / 2 = 2.5000 |
\ |
Arithmetic | Divides the right operand by the left operand | 5 \ 2 = 0.4000 |
+ |
Arithmetic | Adds two values together | 5 + 2 = 7 |
. |
Arithmetic | Modifies operators to perform element-by-element arithmetic versus matrix arithmetic. There is no modification if you’re operating on scalars (ordinary numbers). | [1,2]*[3;4] = 11
|
= |
Assignment | Assigns the value found in the right operand to the left operand. | MyVar = 2 results in MyVar containing 2 |
bitand |
Bitwise | Performs a logical and of the bits in two numbers. | bitand(4, 5) = 4 |
bitor |
Bitwise | Performs a logical or of the bits in two numbers. | bitor(4, 5) = 5 |
bitget |
Bitwise | Obtains the value of the bit at a specific location. | bitget(4, 3) = 1 |
bitset |
Bitwise | Changes the bit at the specified location. | bitset(4, 1, 1) = 5 |
bitshift |
Bitwise | Shifts the bits the specified number of positions. | bitshift(2, 1) = 4 |
bitxor |
Bitwise | Performs a logical exclusive or on the bits in two numbers. | bitxor(4, 5) = 1 |
and |
Logical | Determines whether both operands are true. | and(true, true) = 1 (or true)
|
not |
Logical | Negates the truth value of a single operand. A true value becomes false and a false value becomes true. | not(true) = 0
|
or |
Logical | Determines when one of two operands is true. | or(true, true) = 1
|
xor |
Logical | Determines when one and only one of the operands is true. | xor(true, true) = 0
|
all |
Logical | Determines if all of the array elements are non-zero or true. | all([1, 2, 3, 4]) = 1
|
any |
Logical | Determines if any of the array elements are non-zero or true. | any([0, 1, 0, 0]) = 1
|
~= |
Relational | Determines whether two values are not equal. | 1 ~= 2 is 1 (or true) |
< |
Relational | Verifies that the left operand value is less than the right operand value. | 1 < 2 is 1 |
<= |
Relational | Verifies that the left operand value is less than or equal to the right operand value. | 1 <= 2 is 1 |
== |
Relational | Determines whether two values are equal. Notice that the relational operator uses two equals signs. A mistake many developers make is using just one equals sign, which results in one value being assigned to another. | 1 == 2 is 0 |
> |
Relational | Verifies that the left operand value is greater than the right operand value. | 1 > 2 is 0 |
>= |
Relational | Verifies that the left operand value is greater than or equal to the right operand value. | 1 >= 2 is 0 |
- |
Unary | Negates the original value, so that positive becomes negative and vice versa. | —(@@nd4) results in 4 while —4 results in —4 |
+ |
Unary | Provided purely for the sake of completeness. This operator returns the same value you provide as input. | +4 results in a value of 4 |
Live Script Control Summary
Using Live Script controls can make your documents interactive. You can do everything from very simple things, like displaying a Help button, to providing controlled inputs for your algorithm. You can create input form documents or design a test. Using controls gives your application more of a full-fledged application feel without requiring you to get a computer science degree. Not that the experience of using controls is free of some development tricks, but using the MATLAB controls is easier than working with controls in a full-fledged development environment. MATLAB supports these controls:
| Control | Purpose | Description |
| Button | Lets you define the precise moment when an action should occur | After providing all the input required to create a plot, the user clicks the Plot button in your application and sees the resulting plot onscreen. To use the Button control effectively, you must set the Run field for any controls in the document to Nothing. |
| Check Box | Provides logical input with an output of one of two values | The feature is either on or off, the answer is either yes or no, the user either wants to opt in or opt out. |
| Drop-Down List | Contains a set number of input values | The user selects the desired input value from the list, meaning that incorrect input values due to typos and other forms of user error are a thing of the past. Relying on drop-down list boxes instead of requiring the user to type values also makes data entry significantly faster. |
| Edit Field | Provides a convenient means of allowing free-form input from the user | Avoid using the Edit Field control when you can; it creates the potential for a security breach unless you perform a lot of background checks. The Edit Field control is the most flexible of all the controls because you really can perform free-form input. |
| Numeric Slider | Allows control over a value within a specific range | You might want to allow the viewer to choose the number of graphs displayed at any time as part of the plot. Moving the Numeric Slider control’s thumb (the square box that controls its value) to the desired number of graphs will change the appearance of the plot. The advantage of using a numeric slider is that you control the correct input values and don’t need to consider values outside the desired range, thereby reducing application errors. |
Live Editor Coding Buttons
Specialized features can make your coding experience easier and possibly save time as well. MATLAB provides a set of six specialized coding buttons in the Code section of the Live Editor tab. The following table offers a quick summary of how you use each button (or associated speed key) to perform tasks in Live Editor.
| Button Name | Speed Key | Purpose |
| Comment | Ctrl+R | Adds a % in front of each selected line in a group, commenting the code out for testing or debugging. |
| Uncomment | Ctrl+T | Removes the first % in front of each selected line in a group, making the code active again. If the group contains a comment line, only the first % is removed, which means that the comment stays a comment. |
| Wrap Comments | Ctrl+J | Combines lines with a similar indent to make a comment block smaller. Works only with lines that are already commented out. |
| Smart Indent | Ctrl+I | Adds indentation as needed to make the code more readable. MATLAB uses natural code boundaries, such as if…else statements, to make the indentation. |
| Increase Indent | Ctrl+] | Adds a single level of indentation to the selected lines of code. |
| Decrease Indent | Ctrl+[ | Removes a single level of indentation from the selected lines of code. If the selected code is already at the left margin, the button has no effect on that line. |
Line Plot Styles
Whenever you create a plot, you need to identify the sources of information using more than just the lines. Creating a plot that uses differing line types and data point symbols makes the plot much easier for other people to use. The following table contains a listing of the line plot styles.
| Color | Marker | Style | |||
| Code | Line Color | Code | Marker Style | Code | Line Style |
| b | Blue | . | Point | – | Solid |
| g | Green | o | Circle | : | Dotted |
| r | Red | x | X-mark | -. | dash dot |
| c | Cyan | + | Plus | — | Dashed |
| m | Magenta | * | Star | (none) | no line |
| y | Yellow | s | Square | ||
| k | Black | d | Diamond | ||
| w | White | v | Down triangle | ||
| ^ | Up triangle | ||||
| < | Left triangle | ||||
| > | Right triangle | ||||
| p | Five-point star | ||||
| h | Six-point star | ||||
Remember that you can also use these styles with other kinds of plots. For example, a scatterplot can use these styles to define each of the data points. When in doubt, try the styles to see whether they’ll work with your particular plot.
