Description
Bug summary
If one attempts to set the color parameter to a tuple of length 2, a nonsense error message is returned.
Code for reproduction
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 10, 100)
y = np.array([np.sin(x), np.cos(x)]).T
plt.plot(x, y, label=("sin(x)", "cos(x)")) # works
plt.plot(x, y, label=("sin(x)", "cos(x)"), color=("red", "blue")) # causes strange error
plt.legend()
plt.show()Actual outcome
Traceback (most recent call last):
File "/Users/miles/Desktop/thing.py", line 8, in
plt.plot(x, y, label=("sin(x)", "cos(x)"), color=("red", "blue")) # causes error
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/pyplot.py", line 3708, in plot
return gca().plot(
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_axes.py", line 1779, in plot
lines = [*self._get_lines(self, *args, data=data, **kwargs)]
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py", line 296, in call
yield from self._plot_args(
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py", line 534, in _plot_args
return [l[0] for l in result]
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py", line 534, in
return [l[0] for l in result]
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py", line 527, in
result = (make_artist(axes, x[:, j % ncx], y[:, j % ncy], kw,
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py", line 335, in _makeline
seg = mlines.Line2D(x, y, **kw)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/lines.py", line 376, in init
self.set_color(color)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/lines.py", line 1066, in set_color
mcolors._check_color_like(color=color)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/colors.py", line 245, in _check_color_like
if not is_color_like(v):
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/colors.py", line 227, in is_color_like
to_rgba(c)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/colors.py", line 309, in to_rgba
rgba = _to_rgba_no_colorcycle(c, alpha)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/matplotlib/colors.py", line 334, in _to_rgba_no_colorcycle
if alpha is not None and not 0 <= alpha <= 1:
TypeError: '<=' not supported between instances of 'int' and 'str'
Expected outcome
Either: (1) works as expected as passing a tuple to label does, or, if this won't be supported, (2) a more sensical error message is returned, like if ["red", "blue"] were passed.
Additional information
This difficult-to-interpret error seems to be caused by the if statement of line 328 in _to_rgba_no_colorcycle in colors.py, which says if isinstance(c, tuple) and len(c) == 2. If I comment out this if statement, then the error message gives the normal ValueError: ('red', 'blue') is not a valid value for color... message. Of course, it would be great if multiple colors were supported here, but I understand if there is a bigger reason why it is not supported.
Operating system
macOS 14.4.1
Matplotlib Version
3.9.0
Matplotlib Backend
macosx
Python version
3.9.6
Jupyter version
No response
Installation
pip