What are anonymous functions in MATLAB?
In MATLAB, anonymous functions are functions that define other small, unnamed functions without creating separate files. They are useful for defining quick, one-time-use functions or passing functions as arguments to other functions.
How to create anonymous functions
We can create anonymous functions using the @(inputs) expression syntax, where inputs are the function’s input arguments and expression is the function’s operation.
Let’s go through different types of anonymous functions and see their examples.
Single input
Let’s create a function that takes one input.
square = @(x) x.^2;result = square(5); % This will return 25fprintf('The square value is %.2f\n', result);
Explanation
In the code above:
-
Line 1: We create an anonymous function
@(x) x.^2that takes one inputxand returns its square. The function is then assigned to the variablesquare. We can callsquarelike a regular function. -
Line 3: We call
square, which passes5as an input, and stores it in theresultvariable. -
Line 5: We print the value of
result.
Multiple inputs
Anonymous functions can also take multiple inputs. Let’s go through an example and see how it works.
addition = @(a, b) a + b;result = addition(3, 4); % This will return 7fprintf('The square value is %.2f\n', result);
The function above takes two arguments, adds them, and returns the value.
Commonly used functions
These functions are commonly used with functions like arrayfun, cellfun, map, filter, and others where a function is applied element-wise or to each element of an array or cell array.
Let’s go through an example and see how it works.
values = [1, 2, 3, 4, 5];squared_values = arrayfun(@(x) x.^2, values);fprintf('The square values are %.2f\n', squared_values);
Explanation
In the code above:
- We call
arrayfun, which applies the anonymous function,@(x) x.^2, to each element of thevaluesarray, resulting in a new array containing the squares of each element.
What is the output of the following MATLAB code?
nums = [3, 6, 9, 12];
cubed_nums = arrayfun(@(x) x.^3, nums);
fprintf('The cubed numbers are: ');
disp(cubed_nums);
The cubed numbers are: [27, 216, 729, 1728]
The code will produce an error because of incorrect syntax.
The cubed numbers are: 27 216 729 1728
The cubed numbers are: 3, 6, 9, 12
Conclusion
Anonymous functions offer a convenient way to define small, one-time-use functions or pass functions as arguments, enhancing the flexibility and efficiency of code development.
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