[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler #27596

castilma · 2024-01-03T18:06:36Z

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

The text was updated successfully, but these errors were encountered:

WeatherGod · 2024-01-03T18:27:01Z

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 · 2024-01-03T18:33:16Z

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 · 2024-01-03T18:34:15Z

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.

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tacaswell · 2024-01-03T18:38:31Z

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 · 2024-01-03T19:13:41Z

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: ***@***.***>

tacaswell added this to the v3.8.3 milestone Jan 3, 2024

tacaswell added status: confirmed bug Good first issue Open a pull request against these issues if there are no active ones! Difficulty: Medium https://matplotlib.org/devdocs/devel/contribute.html#good-first-issues labels Jan 3, 2024

faisal-fawad mentioned this issue Jan 8, 2024

Fix marker validator with cycler (allow mix of classes) #27613

Merged

2 tasks

QuLogic closed this as completed in #27613 Jan 10, 2024

conradhaupt mentioned this issue Feb 19, 2025

[Bug]: Markers with string-type integer values are converted to integers in cycler and matplotlibrc #29646

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[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler #27596

[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler #27596

castilma commented Jan 3, 2024

WeatherGod commented Jan 3, 2024 via email

tacaswell commented Jan 3, 2024

github-actions bot commented Jan 3, 2024

tacaswell commented Jan 3, 2024

WeatherGod commented Jan 3, 2024 via email

[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler #27596

[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler #27596

Comments

castilma commented Jan 3, 2024

Bug summary

Code for reproduction

Actual outcome

Expected outcome

Additional information

Operating system

Matplotlib Version

Matplotlib Backend

Python version

Jupyter version

Installation

WeatherGod commented Jan 3, 2024 via email

tacaswell commented Jan 3, 2024

github-actions bot commented Jan 3, 2024

Good first issue - notes for new contributors

tacaswell commented Jan 3, 2024

WeatherGod commented Jan 3, 2024 via email