| MATLAB Function Reference | |
Display help for MATLAB functions in Command Window
Syntax
Description
help
lists all primary help topics in the Command Window. Each main help topic corresponds to a directory name on the MATLAB search path.
help /
lists all operators and special characters, along with their descriptions.
help function
displays M-file help, which is a brief description and the syntax for function, in the Command Window. If function is overloaded, help displays the M-file help for the first function found on the search path, and lists the overloaded functions.
help toolbox/
displays the contents file for the specified directory named toolbox. It is not necessary to give the full pathname of the directory; the last component, or the last several components, are sufficient.
help displays the M-file help for toolbox/function
function that belongs to the toolbox directory.
help displays M-file help describing the syntax used in MATLAB commands and functions.syntax
Note
M-file help displayed in the Command Window uses all uppercase characters for the function and variable names to make them stand out from the rest of the text. When typing function names, however, use lowercase characters. Some functions for interfacing to Java do use mixed case; the M-file help accurately reflects that and you should use mixed case when typing them. For example, the javaObject function uses mixed case. |
Creating Online Help for Your Own M-Files
The MATLAB help system, like MATLAB itself, is highly extensible. You can write help descriptions for your own M-files and toolboxes using the same self-documenting method that MATLAB M-files and toolboxes use.
The help function lists all help topics by displaying the first line (the H1 line) of the contents files in each directory on the MATLAB search path. The contents files are the M-files named Contents.m within each directory.
Typing help topic, where topic is a directory name, displays the comment lines in the Contents.m file located in that directory. If a contents file does not exist, help displays the H1 lines of all the files in the directory.
Typing help topic, where topic is a function name, displays help for the function by listing the first contiguous comment lines in the M-file topic.m.
Create self-documenting online help for your own M-files by entering text on one or more contiguous comment lines, beginning with the second line of the file (first line if it is a script). For example, an abridged version of the M-file angle.m provided with MATLAB could contain
function p = angle(h) % ANGLE Polar angle. % ANGLE(H) returns the phase angles, in radians, of a matrix % with complex elements. Use ABS for the magnitudes. p = atan2(imag(h),real(h));
When you execute help angle, lines 2, 3, and 4 display. These lines are the first block of contiguous comment lines. After the first contiguous comment lines, enter an executable statement or blank line, which effectively ends the help section. Any later comments in the M-file do not appear when you type help for the function.
The first comment line in any M-file (the H1 line) is special. It should contain the function name and a brief description of the function. The lookfor function searches and displays this line, and help displays these lines in directories that do not contain a Contents.m file.
Creating Contents Files for Your Own M-File Directories
A Contents.m file is provided for each M-file directory included with the MATLAB software. If you create directories in which to store your own M-files, you should create Contents.m files for them too. To do so, simply follow the format used in an existing Contents.m file.
Examples
displays help for the datafun directory.
displays help for the fft function.
To prevent long descriptions from scrolling off the screen before you have time to read them, enter more on, and then enter the help function.
See Also
doc, helpbrowser, helpwin, lookfor, more, partialpath, path, what, which
| | hdftool | helpbrowser | |