Help :: Programming Tips (Programming)

Programming

Help

This section covers the following topics:

Using the Help Browser

Open the Help browser from the MATLAB Command Window using one of the following:

Click on the question mark symbol in the toolbar.
Select Help -> MATLAB Help from the menu.
Type the word doc at the command prompt.

Some of the features of the Help browser are listed below.

Feature
Description

Product Filter
Establish which products to find help on.

Contents
Look up topics in the Table of Contents.

Index
Look up help using the documentation Index.

Search
Search the documentation for one or more words.

Demos
See what demos are available; run selected demos.

Favorites
Save bookmarks for frequently used Help pages.

Feature	Description
Product Filter	Establish which products to find help on.
Contents	Look up topics in the Table of Contents.
Index	Look up help using the documentation Index.
Search	Search the documentation for one or more words.
Demos	See what demos are available; run selected demos.
Favorites	Save bookmarks for frequently used Help pages.

For more information: See Finding Information with the Help Browser in the MATLAB Desktop Tools and Development Environment documentation.

Help on Functions from the Help Browser

To find help on any function from the Help browser, do either of the following:

Select the Contents tab of the Help browser, open the Contents entry labeled MATLAB, and find the two subentries shown below. Use one of these to look up the function you want help on.

- Functions -- Categorical List

- Functions -- Alphabetical List

Type doc functionname at the command line.

Help on Functions from the Command Window

Several types of help on functions are available from the Command Window:

To list all categories that you can request help on from the Command Window, just type

```
   help
```

To see a list of functions for one of these categories, along with a brief description of each function, type help category. For example,

```
   help datafun
```

To get help on a particular function, type help functionname. For example,

```
   help sortrows
```

Topical Help

In addition to the help on individual functions, you can get help on any of the following topics by typing help topicname at the command line.

Topic Name
Description

arith
Arithmetic operators

relop
Relational and logical operators

punct
Special character operators

slash
Arithmetic division operators

paren
Parentheses, braces, and bracket operators

precedence
Operator precedence

datatypes
MATLAB data types, their associated functions, and operators that you can overload

lists
Comma separated lists

strings
Character strings

function_handle
Function handles and the @ operator

debug
Debugging functions

java
Using Java from within MATLAB

fileformats
A list of readable file formats

changeNotification
Windows directory change notification

Topic Name	Description
`arith`	Arithmetic operators
`relop`	Relational and logical operators
`punct`	Special character operators
`slash`	Arithmetic division operators
`paren`	Parentheses, braces, and bracket operators
`precedence`	Operator precedence
datatypes	MATLAB data types, their associated functions, and operators that you can overload
`lists`	Comma separated lists
`strings`	Character strings
`function_handle`	Function handles and the `@` operator
`debug`	Debugging functions
`java`	Using Java from within MATLAB
`fileformats`	A list of readable file formats
`changeNotification`	Windows directory change notification

Paged Output

Before displaying a lengthy section of help text or code, put MATLAB into its paged output mode by typing more on. This breaks up any ensuing display into pages for easier viewing. Turn off paged output with more off.

Page through the displayed text using the space bar key. Or step through line by line using Enter or Return. Discontinue the display by pressing the Q key or Ctrl+C.

Writing Your Own Help

Start each program you write with a section of text providing help on how and when to use the function. If formatted properly, the MATLAB help function displays this text when you enter

```
help functionname
```

MATLAB considers the first group of consecutive lines immediately following the function definition line that begin with % to be the help section for the function. The first line without % as the left-most character ends the help.

For more information: See Help Text in the MATLAB Desktop Tools and Development Environment documentation.

Help for Subfunctions and Private Functions

You can write help for subfunctions using the same rules that apply to main functions. To display the help for the subfunction mysubfun in file myfun.m, type

```
help myfun>mysubfun
```

To display the help for a private function, precede the function name with private/. To get help on private function myprivfun, type

```
help private/myprivfun
```

Help for Methods and Overloaded Functions

You can write help text for object-oriented class methods implemented with M-files. Display help for the method by typing

```
help classname/methodname
```

where the file methodname.m resides in subdirectory @classname.

For example, if you write a plot method for a class named polynom, (where the plot method is defined in the file @polynom/plot.m), you can display this help by typing

```
help polynom/plot
```

You can get help on overloaded MATLAB functions in the same way. To display the help text for the eq function as implemented in matlab/iofun/@serial, type

```
help serial/eq
```

Command and Function Syntax Development Environment