Is there any way to determine when a function was removed from MATLAB?

I was working on a tool that scrapes webdocs to determine the version when a given function was introduced to MATLAB -- but that's really only a partial description of the general goal. When setting up version checks in code, one would want to know what versions offer the function and which ones don't. That means it would be desirable to know when a function was introduced and (if so) when it was removed.

In the latter case, I cannot think of any practical and reliable means of determining that. The webdocs don't exist for removed functions -- or at least not for some. Webdocs (but no removal version) exist for this, but not for isgray(). For the few I know of off the top of my head, I don't know of anywhere that they're listed, let alone with version information. Searching the totality of release notes isn't really practical, and probably isn't reliable either. Release notes mention wavread(), but not isgray(), so I assume not everything is mentioned.

Any ideas? Please tell me I missed something obvious and convenient.

[Star Strider]

A source for this sort of version information (function introduction, name changes — for example from simple to simplify — and deprecation) would be really helpful.

I suggest that you Contact Support and put in an enhancement request for something like this. At the very least, all such information would be put in a specific place, so easily searchable.

For raising this issue: +1

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Answer 1

[DGM]

The current incarnation of when() with is on the FEX:

https://www.mathworks.com/matlabcentral/fileexchange/97272-a-slightly-more-robust-version-of-when

It's been working okay so far, and I use it pretty much every day.

If anyone wants a thorough review of the limitations of any such tool, read the internal comments.

Answer 2

[Image Analyst]

You can check the release notes page:

https://www.mathworks.com/help/matlab/release-notes.html

twist the items that say "Functionality being removed or changed"

[DGM]

Like I said, the release notes really aren't a practical option, especially not for programmatic access.

The web version is a narrow rolling ~3 year window, which makes it mostly useless for the purpose. This is compounded by the fact that the pages require JS in order to function, so I don't know of a simple and efficient way to scrape them. To make matters worse, you'd have to know what toolboxes to check, otherwise you'd have to check each page for each toolbox and each version. It might be possible to scrape them all now and build a lookup table for runtime use, but it would still only go back to R2018a. Most of the great purges that I'm familiar with happened before then.

There are PDF release notes available back to ~R2012b, and I'd considered scraping them and building a table, but as far as I can tell, the PDF release notes only cover the base MATLAB, but not all the toolboxes. I haven't found any corresponding PDF release notes for e.g. IPT or other toolboxes, so the PDF option really only addresses a small fraction of the problem.