Understanding the structfun() or cellfun() commands (2024)

Thank you dpb for the answer, which does work as needed.

A couple follow up comments/ questions if I may:

1) I learned that the {} around Files.name creates the cell array of the file names. Such as,

The reason I need to {} is to create the array? Otherwise the command,

only knows to grab the first file's name?

2) I do not understand my initial error with the cellfun() command. If you couple please enlighten me on this regard. It seems like the function was doing something but the indexing was incorrect?

3) Could I still use a cellfun() to get the numbers in front of the file name? For example:

I want to understand how to use an arbitrary function inside the cellfun() command to be able to use them in the future. I understand the case of simpler functions, such as:

Most appreciated.

1) Try at the command line and see what Files.name returns. (Hint: search for "comma-separated list" in doc)

2) Since the first failed, I don't know what the content of the cell array was when you tried it so it's not possible to say just what, but probably you had a smaller array than thought and passed inconsistent ones

3a) Sure, but why? You want to avoid loops; cellfun is a loop in sheep's clothing; underneath it is the loop with more overhead than just the direct for...end construct. It has its place, certainly, but isn't always the better solution. But, for illustration

3b) As the above illustrates, you write an anonymous function in place of the function handle--it can be any one-line expression. Or, if you can't manage it in one line, use a handle to the m-file function you write. NB: one feature of anonymous functions is that the embed any workspace variables not in their argument list in the function body itself -- the same result as above could be obtained by

where the Files struct is embedded in the anonymous function. While not optimal here, this can be extremely useful when other parameters are needed to evaluate the function.

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