[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler

[castilma]

Bug summary

I want to cycle between multiple markerstyles, including those with a numeric value like CARETRIGHT as documented here, but I get an exception if I add one of those.

Code for reproduction

#!/usr/bin/env python3

from cycler import cycler
import matplotlib.pyplot as plt
import matplotlib.markers as mk

cycle = cycler(marker=["+",mk.CARETRIGHT])

t=[0,1]
y=[5,6]

plt.rc('axes', prop_cycle=cycle)
plt.plot(t,y)
plt.show()

Actual outcome

Traceback (most recent call last):
  File "/home/mcd/bugs/bug-cycler.py", line 11, in <module>
    plt.rc('axes', prop_cycle=cycle)
  File "/usr/lib/python3.11/site-packages/matplotlib/pyplot.py", line 670, in rc
    matplotlib.rc(group, **kwargs)
  File "/usr/lib/python3.11/site-packages/matplotlib/__init__.py", line 1062, in rc
    rcParams[key] = v
    ~~~~~~~~^^^^^
  File "/usr/lib/python3.11/site-packages/matplotlib/__init__.py", line 734, in __setitem__
    raise ValueError(f"Key {key}: {ve}") from None
ValueError: Key axes.prop_cycle: Could not convert 5 to str

Expected outcome

A plot using CARETLEFT as marker.

Additional information

This seems like it has to do with the fact, that some markers are referred to by number and not by a string like "+".
I don't know whether the problem is in matplotlib, cycler or the combination of both.

Operating system

Artix Linux

Matplotlib Version

3.8.1

Matplotlib Backend

GTK4Agg

Python version

Python 3.11.6

Jupyter version

No response

Installation

Linux package manager

[WeatherGod]

Looks like the validator for the `marker` property is a stringlist validator, so it is trying to coerce things into strings. Probably should update the validator.

…

On Wed, Jan 3, 2024 at 1:06 PM castilma ***@***.***> wrote: Bug summary I want to cycle between multiple markerstyles, including those with a numeric value like CARETRIGHT as documented here <https://matplotlib.org/stable/api/markers_api.html#module-matplotlib.markers>, but I get an exception if I add one of those. Code for reproduction #!/usr/bin/env python3 from cycler import cyclerimport matplotlib.pyplot as pltimport matplotlib.markers as mk cycle = cycler(marker=["+",mk.CARETRIGHT]) t=[0,1]y=[5,6] plt.rc('axes', prop_cycle=cycle)plt.plot(t,y)plt.show() Actual outcome Traceback (most recent call last): File "/home/mcd/bugs/bug-cycler.py", line 11, in <module> plt.rc('axes', prop_cycle=cycle) File "/usr/lib/python3.11/site-packages/matplotlib/pyplot.py", line 670, in rc matplotlib.rc(group, **kwargs) File "/usr/lib/python3.11/site-packages/matplotlib/__init__.py", line 1062, in rc rcParams[key] = v ~~~~~~~~^^^^^ File "/usr/lib/python3.11/site-packages/matplotlib/__init__.py", line 734, in __setitem__ raise ValueError(f"Key {key}: {ve}") from None ValueError: Key axes.prop_cycle: Could not convert 5 to str Expected outcome A plot using CARETLEFT as marker. Additional information This seems like it has to do with the fact, that some markers are referred to by number and not by a string like "+". I don't know whether the problem is in matplotlib, cycler or the combination of both. Operating system Artix Linux Matplotlib Version 3.8.1 Matplotlib Backend GTK4Agg Python version Python 3.11.6 Jupyter version *No response* Installation Linux package manager — Reply to this email directly, view it on GitHub <#27596>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACHF6ELTISA2WV6D5ACXBLYMWM3TAVCNFSM6AAAAABBLZNEFCVHI2DSMVQWIX3LMV43ASLTON2WKOZSGA3DINBUGUZTKOI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[tacaswell]

More specifically

matplotlib/lib/matplotlib/rcsetup.py

Line 648 in 8703dc5

'marker': validate_stringlist,

needs to be updated to accept the int(/enum) values.

In [13]: plt.rcParams['lines.marker'] = mk.CARETRIGHT
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[13], line 1
----> 1 plt.rcParams['lines.marker'] = mk.CARETRIGHT

File /usr/lib/python3.11/site-packages/matplotlib/__init__.py:734, in RcParams.__setitem__(self, key, val)
    732         cval = self.validate[key](val)
    733     except ValueError as ve:
--> 734         raise ValueError(f"Key {key}: {ve}") from None
    735     self._set(key, cval)
    736 except KeyError as err:

ValueError: Key lines.marker: Could not convert 5 to str

is a simpler way exercise the same issue.

[github-actions]

Good first issue - notes for new contributors

This issue is suited to new contributors because it does not require understanding of the Matplotlib internals. To get started, please see our contributing guide.

We do not assign issues. Check the Development section in the sidebar for linked pull requests (PRs). If there are none, feel free to start working on it. If there is an open PR, please collaborate on the work by reviewing it rather than duplicating it in a competing PR.

If something is unclear, please reach out on any of our communication channels.

[tacaswell]

Steps:

• update the marker validator to accept all valid marker specifications (atleast the integers, maybe the path and Marker classes as well)
• add a test
• add a whats new (if extended past integers)

Good first issue because this is very narrowly scoped, but medium because there is some meta-programming in the validator code. Some thought will need to be given to writing a validator that works for both "live" objects and for strings coming from reading and .matplotlibrc.

[WeatherGod]

The problem might exist in several places such as https://github.com/matplotlib/matplotlib/blob/8703dc5682d3655258d8917c1f8ef63cb1576dbb/lib/matplotlib/rcsetup.py#L911

…

On Wed, Jan 3, 2024 at 1:38 PM Thomas A Caswell ***@***.***> wrote: Steps: - update the marker validator to accept all valid marker specifications (atleast the integers, maybe the path and Marker classes as well) - add a test - add a whats new (if extended past integers) Good first issue because this is very narrowly scoped, but medium because there is some meta-programming in the validator code. Some thought will need to be given to writing a validator that works for both "live" objects and for strings coming from reading and .matplotlibrc. — Reply to this email directly, view it on GitHub <#27596 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACHF6GY7VSBKB7VZ77OGN3YMWQTFAVCNFSM6AAAAABBLZNEFCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQNZVHAYDCOJXGE> . You are receiving this because you commented.Message ID: ***@***.***>