In MATLAB, the cell data type is a powerful container that can hold heterogeneous data types within a single element. This flexibility comes with the added benefit of functionality via cellfun, a built-in MATLAB function that returns an array of results after applying a specified function to each element within the cell.

cellfun is a versatile and powerful tool in MATLAB that can streamline your code and reduce the need for loops and conditional statements. By leveraging the full potential of cellfun, you can compute complex computations efficiently and conveniently, saving you valuable time and resources.

In this article, we'll explore how to use cellfun in MATLAB to perform common operations on cell arrays.

Basic Syntax and Usage of cellfun

The basic syntax of cellfun is straightforward. The function expects two inputs- the function handle and the cell array. The function handle specifies the function to call on each cell element, and the cell array is the container containing the elements to which the function is applied.

The general syntax for cellfun is as follows:

OutputArray = cellfun(functionHandle, inputCellArray)

where OutputArray is the array resulting from applying the function on each element in the inputCellArray.

Example Usage: Getting the Length of Each String Element in a Cell Array

Suppose we have a cell array containing strings of varying length. We want to obtain the length of each string element and store the result in another cell array.

We start by defining the input cell array, which in this case, is a cell array containing strings of varying length.

inputArray = {'apple', 'banana', 'cherry', 'pear'}

We can obtain the length of each string by passing the built-in MATLAB function, strlength, as the function handle to cellfun. Here's the code to achieve that:

outputArray = cellfun(@strlength, inputArray, 'UniformOutput', false)

Let's break down the above syntax:

- The first argument is the function handle which is @strlength, indicating the function to get the length of each string element.

- The second argument is the input cell array that contains the elements to which the function is applied.

- The third argument, 'UniformOutput', false, specifies that the output size may be different for each element in the input cell array.

The resulting array, outputArray, now contains the length of each string element in the input cell array.

Example Usage: Checking If Each Element in a Cell Array is a String

To check if each element in a cell array is a string or not, we can use the isstring function as the function handle in cellfun. The code is similar to the previous example but with the isstring function as the function handle, as shown below:

inputArray = {'apple', 25, 'cherry', 75}

outputArray = cellfun(@isstring, inputArray)

Here's the breakdown of the above code:

- We start by defining the input cell array that contains strings and numeric elements.

- We specify the function handle – @isstring – which is the built-in function that checks if the input is a string.

- We call cellfun, passing in the function handle and the input cell array, and then assign the result to the variable, outputArray.

The resulting outputArray is a logical array that indicates if each element in the input cell array is a string.

Advanced Usage: Applying a Function that Returns Multiple Outputs

cellfun can apply a function that also returns multiple outputs. In this case, we can use the 'UniformOutput', false argument in cellfun to indicate that the resulting cell array may have varying sizes. Here's an example of how to return multiple outputs for each element in a cell array:

inputArray = {'apple', 'banana', 'cherry', 'pear'}

% Define the function to get the first and last character of each string

getFirstLastChar = @(x) {x(1), x(end)}

% Call the function and assign the result to a new variable, outputArray

outputArray = cellfun(getFirstLastChar, inputArray, 'UniformOutput', false)

The resulting outputArray is a cell array containing two elements for each input element, with the first element being the first character, and the second element being the last character.

Conclusion

In summary, cellfun is a powerful and flexible function in MATLAB that provides a convenient way to compute complex computations on cell arrays efficiently. It works by applying a specified function to each element within a cell array, helping you streamline your code and reduce the need for loops and conditional statements.

By leveraging the full potential of cellfun, you can perform a wide variety of operations on cell arrays with ease. I hope this article has given you an insight into how to use cellfun in MATLAB and how it can support your code development.