py.list bug in R2024a

I believe I'm experiencing a bug in R2024a with py.list. After a clear all, I get the error No module or function named 'list'.:

clear all;res = py.list({"Name1","Name2","Name3"});

In this interface, the code runs just fine. When I run it locally, I get this:

>> clear all;res = py.list({"Name1","Name2","Name3"})

No module or function named 'list'.

I can get py.list to work again if I use another Python command. For example, this works:

>> handlers = py.logging.getLogger().handlers;

>> res = py.list({"Name1","Name2","Name3"});

>> clear all;res = py.list({"Name1","Name2","Name3"});

No module or function named 'list'.

I'm running MATLAB Version: 24.1.0.2628055 (R2024a) Update 4. I cannot replicate on R2023b.

Answer 1

[Steven Lord]

See Bug Report 3293694.

[Tom Grieve]

Thank you! I don't know how I missed that bug report.

[Steven Lord]

If you searched the bug reports to try to find information about this bug, do you happen to remember what you searched for? Perhaps there's some words or phrases we could add to the report to make it more descriptive and/or discoverable.

[Tom Grieve]

I can find the bug report now with no problem. I'm not sure what I was searching for, but I think I only used "python" as a keyword. I didn't connect my use of "clear all" with the behavior until after I searched, so the name of that bug report may not have meant anything to me.

[Steven Lord]

We tweaked the summary of the bug report to include part of the error message, hopefully that will make it more discoverable when people search for it.

Answer 2

[Avni Agrawal]

Hi @Tom Grieve,

I understand that you are encountering an error when trying to access Python classes after using clear all in the command line for the R2024a release. I experienced a similar issue, and I found a workaround that worked for me. Executing clear classes allows MATLAB to locate and recreate the Python modules. For example:

clear all;res = py.list({"Name1","Name2","Name3"});
clear classes;
res = py.list({"Name1","Name2","Name3"});

I hope this helps!

[Tom Grieve]

Thanks for your help! I'll have to try this workaround and see if it works better than mine for my application.