##### Cheat Sheet

# MATLAB For Dummies Cheat Sheet

MATLAB is an incredibly flexible environment that you can use to perform all sorts of math tasks. A large array of engineering and science disciplines can use MATLAB to meet specific needs in their environment. Using such a complex environment can prove daunting at first, but this Cheat Sheet can help: Get to know common MATLAB commands; become familiar with common operators and precedence; and learn to recognize line plot styles.

## 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 of 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 |

format compact | Removes extraneous spaces from the Command window |

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 orfile> |
Displays help documentation for the <command> orcomments in files you’ve created |

iskeyword | Displays a list of all the MATLAB keywords |

iskeyword <name> |
Determines whether <name> is akeyword |

load <filename> | Loads the file containing variables to the Workspace window |

more off | Displays output using standard scrolling so that all of the output appears at one time |

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> tothe specified < value> |

## MATLAB Common Operator Summary

You need to know which operators MATLAB supports, but remember them all isn’t easy. The following table provides a brief summary of the operators that MATLAB supports.

Operator | Type | Description | Example |
---|---|---|---|

– | Arithmetic | Subtracts the right operand from the 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 by 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 vis-à-vis matrix arithmetic. You receive no modification if you’re operating on scalars (ordinary numbers). |
[1,2]*[3;4] = 11 [1,2].*[3,4] = [3,8] |

= | 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)
and(true, false) = 0 (or false) and(false, false) = 0 and(false, true) = 0 |

not | Logical | Negates the truth value of a single operand. A true value becomes false and a false value becomes true. |
not(true) = 0 not(false)=1 |

or | Logical | Determines when one of two operands are true. | or(true, true) = 1 or(true, false) = 1 or(false, false) = 0 or(false, true) = 1 |

xor | Logical | Determines when one and only one of the operands is true. | xor(true, true) = 0 xor(true, false) = 1 xor(false, false) = 0 xor(false, true) = 1 |

all | Logical | Determines whether all the array elements are nonzero or true. |
all([1, 2, 3, 4]) = 1 all([0, 1, 2, 3]) = 0 |

any | Logical | Determines whether any of the array elements are nonzero or true. |
any([0, 1, 0, 0]) = 1 any([0, 0, 0, 0]) = 0 |

~= | 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. |
-(-4) results in 4 while -4 results in -4 |

+ | Unary | Provided purely for the sake of completeness. This operator returns the same value that you provide as input. |
+4 results in a value of 4 |

## MATLAB Operator Precedence

Knowing the order in which tasks are performed is essential. Otherwise, the formulas you type won’t work as expected and you’ll obtain errant results. The following table shows the order in which MATLAB evaluates various operators.

You can also remember operator precedence using the PEMDAS acronym, which stands for Parentheses, Exponent, Multiply And Divide, Add and Subtract.

Operator | Description |
---|---|

() | Parentheses are used to group expressions and to override the default precedence so that you can force an operation of lower precedence (such as addition) to take precedence over an operation of higher precedence (such as multiplication). |

.‘ .^ ‘ ^ | Transpose, power, complex conjugate transpose, matrix power. |

+ – ~ | Unary operators interact with a single variable or expression. |

.* ./ . * / | Multiplication and division(both right and left). |

+ – | Addition and subtraction. |

: | Colon operator (used for ranges). |

<= < > >= | Comparison operators. |

== ~= | Equality operators. |

& | | Logical operators (element-wise). |

&& || | Logical operators (short-circuit). |

## Line Plot Styles in MATLAB

Whenever you create a plot in MATLAB, 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.

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 | 5-point star | ||||

h | 6-point star |

Remember that you can also use these styles with other kinds of plots. For example, a scatter plot can use these styles to define each of the data points. When in doubt, try the styles to see whether they work with your particular plot.