You can pass function handles in calls to other functions often called function functions. You can also store function handles in data structures for later use for example, as Handle Graphics callbacks.
At the time you create a function handle, the function you specify must be on the MATLAB path and in the current scope. This condition does not apply when you evaluate the function handle. You can, for example, execute a subfunction from a separate out-of-scope M-file using a function handle as long as the handle was created within the subfunction's M-file in-scope. Execute the function by calling it by means of the function handle, handle.
This includes using function handles in structures and cell arrays:. For nonoverloaded functions, subfunctions, and private functions, a function handle references just the one function specified in the functionname syntax.
When you evaluate an overloaded function by means of its handle, the arguments the handle is evaluated with determine the actual function that MATLAB dispatches to. Examples Example 1 -- Constructing a Handle to a Named Function The following example creates a function handle for the humps function and assigns it to the variable fhandle.
Pass the handle to another function in the same way you would pass any argument. This example passes the function handle just created to fminbndwhich then minimizes over the interval [0. The fminbnd function evaluates the humps function handle.
A small portion of the fminbnd M-file is shown below. In line 1, the funfcn input parameter receives the function handle humps that was passed in. The statement, in lineevaluates the handle. Example 2 -- Constructing a Handle to an Anonymous Function The statement below creates an anonymous function that finds the square of a number.
The operator constructs a function handle for this function, and assigns the handle to the output variable sqr. As with any function handle, you execute the function associated with it by specifying the variable that contains the handle, followed by a comma-separated argument list in parentheses.
The syntax is. Because sqr is a function handle, you can pass it in an argument list to other functions. The code shown here passes the sqr anonymous function to the MATLAB quad function to compute its integral from zero to one:.MATLAB Help - function headers
See Also str2funcfunc2strfunctionsisa.Documentation Help Center. This example shows how to provide help for the programs you write. Help text appears in the Command Window when you use the help function. Create help text by inserting comments at the beginning of your program. If your program includes a function, position the help text immediately below the function definition line the line with the function keyword.
If the function contains an arguments block, you also can position the help text immediately below the arguments block.
For example, create a function in a file named addme. When you type help addme at the command line, the help text displays in the Command Window:. The first help text line, often called the H1 line, typically includes the program name and a brief description. The Current Folder browser and the help and lookfor functions use the H1 line to display information about the program.
If the function exists on the search path or in the current folder, the help command displays each of these function names as a hyperlink to its help. Otherwise, help prints the function names as they appear in the help text. You can include hyperlinks in the form of URLs to Web sites in your help text.
Within the anchor, use a matlab: statement to execute a web command. The help system ignores any comment lines that appear after the help text block. When multiple programs have the same name, the help command determines which help text to display by applying the rules described in Function Precedence Order. Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select:. Select the China site in Chinese or English for best site performance.
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Functions are the basis of all scripting and programming languages. With functions, you can make your applications do anything you want. This instruction set assumes you have basic knowledge of MATLAB, such as how to open a script file and how to perform simple data operations. Log in Facebook Loading Google Loading Civic Loading No account yet? Create an account.
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Related Articles. This button will be on the upper left side of your screen. Type your function name. The name of your function should be the name of your file, so when you save this new script file it will be the name of your file. In this case, for example, you can name our function slope-equation. Type the inputs of your function in between the parenthesis. An input is something you need the user to give to you. Comment on what each input is.
Repeat this for each 3 inputs. Commenting is useful in programming for you and others who modify your program to understand all the variables and things you have done and how they are defined.
Type in the operation you want your program to do using your inputs. What this means, in this case, is you want your equation to define a variable y as the product of our input m and x and then add the y intercept value b to it. In line 5, you define your equation. Do not forget the semicolon this semicolon suppresses the output! What does that mean? Use an fprintf statement to output the result of your equation.There are two equivalent ways i.
The first is simply to type at the command prompt in the MATLAB command window "help" followed by the name of the command or function for which you want help. Here is how you access the help information for the date command. In general, when returning help information about some command or function, MATLAB will also suggest similar commands or functions in this way. Go ahead now and try using the help command; type "help date", "help now", and even "help help" there is even help information for the help command itself!
Getting Help a Screenful at a Time. You probably noticed that when you typed "help help" at the command prompt, the help information that was returned to you was too long to fit on one screen, and thus what you ended up with in the MATLAB command window's screen was only about the last half of the help information for "help". You could just go to the beginning of the help text by using the scroll bar at the right side of the window, and scrolling up to the beginning of the returned help text.
However, it would be nice if there were some way you could have MATLAB return the information to you one screen at a time; then, after reading one screenful of the help text you could just hit a key on the keyboard and move on to the next screenful. Happily, there is in fact a way to do this with the "more" command.
The way it works is as follows. If you type "more on" at the command prompt, then all help information returned after that will be presented in readable, screen-at-a-time chunks with the text "--more--" at the bottom ; pressing the space bar will then move you to the next screenful of help text i.
Typing "more off" at the command prompt will revert to the default behavior i. Go ahead now and try using the "more" command; type "more on" and then "help help" and then the space bar or other keys to progress through the help text. Functional Categories. For example, there is one functional category called "timefun" and the "date" and "now" commands are members of this functional category. In addition, you can get help information about a particular functional category, and its member commands and functions, by simply typing at the command prompt "help" followed by the name of the functional category.
For example, typing "help timefun" will give you information about the "timefun" functional category:. Current date and time. Basic functions. Date functions. Timing functions. Searching for Commands. Recall that "help" will display the help text for some command or function, but you have to know the exact name of the command or function in order to be able to get this help text. What if you don't have any particular command or function in mind, or don't know the exact name, but rather would like to get a list of all commands or functions related to some word?
This is precisely what the "lookfor" command can do for you. At the command prompt, you type "lookfor" and then a keyword, and MATLAB will search the help texts of all commands and functions. Any command or function whose first line of help text contains the given keyword will be returned by the "lookfor" command.
You should be warned, however, that the "lookfor" command can take a long time to complete.Documentation Help Center.
Some help text displays the names of functions in uppercase characters to make them stand out from the rest of the text. When typing these function names, use lowercase. For function names that appear in mixed case such as javaObjecttype the names as shown. Because delete is the name of a function and of several methods, the help text includes a link to a list of the methods with the same name.
Request help for the delete method of the handle class. Display help for the containers package, the Map class, and the isKey method. Not all packages, classes, and associated methods or events require complete specification.
For example, display the help text for the throwAsCaller method of the MException class. Display help for a variable of type datetime. Because t is of type datetimethe help command displays help text for the datetime class. Request help for Daya method of the datetime class. Functionality name, such as the name of a function, method, class, toolbox, or variable, specified as a character vector or string scalar. If name is a variable, help displays the help text for the class of that variable.
To get help for a method of a class, specify the class name and the method name, separated with a period. For example, to get help for the methodname method of the classname class, type help classname.
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Some classes and other packaged items require that you specify the package name. Events, properties, and some methods require that you specify the class name. Separate the components of the name with periods. For example, to get help for the propertyname property of the classname class, type classname. To get help for the classname class in the packagename package, type packagename. To get help for the methodname method of the classname class in the packagename package, type packagename.
If name appears in multiple folders on the MATLAB search path, help displays the help text for the first instance of name found on the search path.
If name is overloaded, help displays a link to a list of the methods with the same name. If name specifies the name or partial path of a folder:. If the folder contains a nonempty Contents. If the folder contains an empty Contents. If the folder does not contain a Contents.
If name is the name of both a folder and a function, the help function displays the associated text for both the folder and the function.Documentation Help Center. Both scripts and functions allow you to reuse sequences of commands by storing them in program files.
Functions provide more flexibility, primarily because you can pass input values and return output values. In addition, functions avoid storing temporary variables in the base workspace and can run faster than scripts. For more information, see Create Functions in Files. Choose a web site to get translated content where available and see local events and offers.
Based on your location, we recommend that you select:. Select the China site in Chinese or English for best site performance. Other MathWorks country sites are not optimized for visits from your location. Toggle Main Navigation. Search Support Support MathWorks. Search MathWorks.
Off-Canvas Navigation Menu Toggle. Trials Trials Aggiornamenti del prodotto Aggiornamenti del prodotto. Functions Programs that accept inputs and return outputs. Select a Web Site Choose a web site to get translated content where available and see local events and offers. Select web site.If function is overloaded, help displays the M-file help for the first function found on the search path, and lists the overloaded functions.
It is not necessary to give the full pathname of the directory; the last component, or the last several components, are sufficient. 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. Typing help topicwhere topic is a directory name, displays the comment lines in the Contents. If a contents file does not exist, help displays the H1 lines of all the files in the directory. Typing help topicwhere topic is a function name, displays help for the function by listing the first contiguous comment lines in the M-file topic.
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. When you execute help anglelines 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. If you create directories in which to store your own M-files, you should create Contents. To do so, simply follow the format used in an existing Contents.
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To prevent long descriptions from scrolling off the screen before you have time to read them, enter more onand then enter the help function. See Also dochelpbrowserhelpwinlookformorepartialpathpathwhatwhich. 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.