Repository navigation
[Bug]: matplotlib.cm.get_cmap() missing #28349
Description
Activity
Duplicate of #28317
This was marked with a deprecation and in 3.8.4 I get the following:
>>> matplotlib.cm.get_cmap("gray") <stdin>:1: MatplotlibDeprecationWarning: The get_cmap function was deprecated in Matplotlib 3.7 and will be removed two minor releases later. Use ``matplotlib.colormaps[name]`` or ``matplotlib.colormaps.get_cmap(obj)`` instead.
Edit: Also note that the get_cmap() is a method on ColormapRegistry there, not at the module level. It isn't super obvious when first looking at the page.
We are seeing multiple reports that the warnings in 3.8 were not seen. We should sort out why and consider putting the API in a micro release with a more visible warning (at maybe a custom AttributeError that gives more context?).
- added a commit that references this issue on Mar 29, 2025
- added a commit that references this issue on Mar 5, 2026
- added 2 commits that reference this issue on Mar 20, 2026
Bug summary
As of matplotlib v3.9, it appears that matplotlib.cm.get_cmap() is missing. It is still available on matplotlib.pyplot.get_cmap(), though.
matplotlib.cm.get_cmap() is still shown in the documentation and I would be surprised if this change was made without some kind of deprecation warning.
Code for reproduction
Actual outcome
AttributeError Traceback (most recent call last)
Cell In[3], line 1
----> 1 cm.get_cmap('gray')
AttributeError: module 'matplotlib.cm' has no attribute 'get_cmap'
Expected outcome
Should return the gray colormap.
Additional information
This works in matplotlib <3.9 and is still shown in the documentation. It is kind of odd that this function is available from two locations, though.
Operating system
Any
Matplotlib Version
3.9.0
Matplotlib Backend
agg
Python version
3.11.9
Jupyter version
No response
Installation
pip