Programming and Data Types

Help

This section covers the following topics:

• Using the Help Browser
• Help on Functions from the Help Browser
• Help on Functions from the Command Window
• Topical Help
• Paged Output
• Writing Your Own Help
• Help for Subfunctions and Private Functions
• Help for Methods and Overloaded Functions

Using the Help Browser

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

• Click on the blue 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

For more information: See Finding Information with the Help Browser in the MATLAB "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 -- By Category

  - 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
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
change_notification	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 "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