Advanced use Passing function handles to other functions Put differently: A function handle (whether in the form or for an anonymous function) is simply a value that can be stored in a variable, just like a numerical matrix can be.
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When storing it in a variable, it has a name in the current workspace and can be changed and cleared just like variables holding numbers. This means the anonymous function can be treated like any other value. Anonymous functions are stored in variablesĪn anonymous function (or, more precisely, the function handle pointing at an anonymous function) is stored like any other value in the current workspace: In a variable (as we did above), in a cell array ( or even in a property (like h.ButtonDownFcn for interactive graphics). Within the scope of f, the variable names between parentheses after the operator are independent from the main workspace variables. Also, in the main workspace x was left untouched. The value of x from the main workspace is not used within f. > f = x+1 % here x refers to a private x variable An example to illustrate this: > x = 3 % x in main workspace The main workspace and the anonymous function's workspace do not know about each other's contents. Instead, they are treated as different variables within the scope of the anonymous function, that is: the anonymous function has its private workspace where the input variables never refer to the variables from the main workspace. Note that using the name of variables in the workspace as one of the input arguments of an anonymous function (i.e., using will not use those variables' values. Input arguments to an anonymous function do not refer to workspace variables The value of c is the value at the time of creation of the anonymous function: > c = 2 Note that if the value of c is set to something different at this point, then f(3) is called, the result would not be different. For example, to use a constant c = 2 in an anonymous function: > c = 2 į(3) used the variable c as a parameter to multiply with the provided x.
![matlab function handle matlab function handle](http://matlab.izmiran.ru/help/techdoc/ref/hg_ea.gif)
Variables in the workspace can be used within the definition of anonymous functions. An example of an anonymous function that accepts three variables: > f = x.^2 + y.^2 - z.^2 In the same fashion anonymous functions can be created to accept more than one variable.
![matlab function handle matlab function handle](https://i.stack.imgur.com/ck6XI.gif)
It is used by passing a value of x to f: > f(pi)Ī vector of values or a variable can also be passed to f, as long as they are used in a valid way within f: > f(1:3) % pass a vector to fĪnonymous functions of more than one variable f now is an anonymous function of x: f(x). This was specified using parentheses (.) directly after the operator. As an example of a custom anonymous function that accepts one variable as its input, sum the sine and cosine squared of a signal: > f = sin(x)+cos(x).^2į f accepts one input argument called x. However, it is useful to create anonymous functions that do custom things that otherwise would need to be repeated multiple times or created a separate function for. It is not obviously useful to create a handle to an existing function, like sin in the example above. Custom anonymous functions Anonymous functions of one variable the peaks function), f() would be used to call it without input arguments. If sin would be a function that accepts zero input arguments (which it does not, but others do, e.g. To use f, arguments are passed to it as if it were the sin function: > f(pi/2)į accepts any input arguments the sin function accepts. Just like (in real life) a door handle is a way to use a door, a function handle is a way to use a function. For example, to create a handle to the sin function (sine) and use it as f: > f = f is a handle to the sin function. Use the operator to create anonymous functions and function handles. That is why they are called anonymous, although they can have a name like a variable in the workspace. However, they do not exist on the MATLAB path like a regular function would, e.g.
![matlab function handle matlab function handle](https://i.ytimg.com/vi/5Q89c4PhoNk/maxresdefault.jpg)
They are functions that exist locally, that is: in the current workspace. Anonymous functions are a powerful tool of the MATLAB language.