Re: Matplotlib "collections" module in recent Python, Matplotlib

On 2025-06-15 04:53, jmhannon.ucdavis--- via Python-list wrote:
> Greetings.  We (the group that I work with) have "inherited" some Python
> scripts that were written years ago, using Python 2.
> 
> We're trying to upgrade the scripts so that they work in our current
> environment:
> 
>      OS: Ubuntu 24.04.2 LTS
>      
>      $ python --version
>      Python 3.11.13
>      
>      >>> matplotlib.__version__
>      '3.10.0'
> 
> 
> The first script that we looked at has a line:
> 
>      cs = plt.contourf(X, Y, data, LevelsNumber,
>                    cmap=plt.cm.nipy_spectral, norm=norm).collections
> 
> If I run that script with python 3, I get a warning:
> 
>      MatplotlibDeprecationWarning: The collections attribute was
>      deprecated in Matplotlib 3.8 and will be removed two minor
>      releases later.
>      cmap=plt.cm.nipy_spectral, norm=norm).collections
> 
> I also get the following error:
> 
>      paths = cs.get_paths()
>              ^^^^^^^^^^^^
>      AttributeError: 'list' object has no attribute 'get_paths'
> 
> The "paths" object that I get appears to be no more than a collection of
> geometric factors, i.e., without additional attributes such as color, for
> instance, and statements such as the following fail:
> 
>      bgra_array = 255*paths[i].get_facecolor()[0]
> 
>      AttributeError: 'Path' object has no attribute 'get_facecolor'
> 
> Unfortunately, all the suggestions that I've found to remedy this suggest
> using the "collections" attribute, which is already in the code, and which as
> I noted above, has been deprecated (maybe eliminated -- 3.10 vs. 3.8) now.
> 
> If you have any suggestions about this, please pass 'em along.  Thanks.
> 
Does this help?

https://discourse.matplotlib.org/t/collections-attribute-deprecation-in-version-3-8/24164