Passing an incorrectly sized colour list to scatter should raise a relevant error #9209

MatthewJA · 2017-09-21T05:14:39Z

If the length of the c argument to matplotlib.pyplot.scatter doesn't match the size of the x and y arguments, a confusing error message is raised: Invalid RGBA argument. Contrast this with the error that results if x and y are not the same size: x and y must be the same size. The error message for an incorrect size c array should be made more clear.

Code for reproduction

import numpy, matplotlib.pyplot as plt
xs, ys = numpy.random.random((2, 10))
c = numpy.random.random(9)
plt.scatter(xs, ys, c=c)

Actual outcome

/usr/local/lib/python3.6/site-packages/matplotlib/colors.py in _to_rgba_no_colorcycle(c, alpha)
    192         # float)` and `np.array(...).astype(float)` all convert "0.5" to 0.5.
    193         # Test dimensionality to reject single floats.
--> 194         raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
    195     # Return a tuple to prevent the cached value from being modified.
    196     c = tuple(c.astype(float))

ValueError: Invalid RGBA argument: 0.58430716187559439

Expected outcome

ValueError: c and x must be the same size

Matplotlib Version: 2.0.2
Python Version: 3.6.1

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

jklymak · 2017-09-21T17:40:08Z

This is fixed in master. Should be fixed for 2.1 release. The error raised is

ValueError: c of shape (9,) not acceptable as a color sequence for x with size 10, y with size 10

jklymak · 2017-09-21T18:49:10Z

Closing - feel free to re-open if you think its not fixed in the upcoming 2.1. Thanks for the report!

jklymak · 2017-09-21T19:48:23Z

Fixed in #7363

PorkShoulderHolder · 2019-02-22T00:21:40Z

I am getting this error ValueError: c of shape (3854,) not acceptable as a color sequence for x with size 3854, y with size 3854 in version 2.2.4 of matplotlib. The error definitely isn't helpful in this case.

sskgp · 2019-06-18T11:28:52Z

@PorkShoulderHolder please change c to have a shape of (n,1) instead of (n,) - this works for me.

weihuaguo · 2019-10-04T21:27:55Z

@sabyagunnersya I try both (n,1) and (n,). Both of them are not working! Is there any other solution? Thanks!
ValueError: c of shape (303262, 1) not acceptable as a color sequence for x with size 303262, y with size 303262
ValueError: c of shape (303262,) not acceptable as a color sequence for x with size 303262, y with size 303262

TTitcombe · 2019-11-19T10:48:04Z

@PorkShoulderHolder @weihuaguo Is this the issue you were seeing? #15727

runnholm · 2019-11-26T13:56:16Z

@PorkShoulderHolder please change c to have a shape of (n,1) instead of (n,) - this works for me.

This works for me as well, but this does not seem like expected behaviour? There is no obvious reason (n,) should not work.

sorenwacker · 2020-06-02T19:47:07Z

LoL, I just got this:

ValueError: 'c' argument has 426 elements, which is not acceptable for use with 'x' with size 426, 'y' with size 426.

tacaswell · 2020-06-02T23:13:51Z

@soerendip What version of Matplotlib? I think we have improved that error message recently.

Do you have a minimal example that will produce that error?

ngmaihuong · 2020-08-10T02:05:39Z

@soerendip What version of Matplotlib? I think we have improved that error message recently.

Do you have a minimal example that will produce that error?

I got the same error:
ValueError: 'c' argument has 59 elements, which is not acceptable for use with 'x' with size 59, 'y' with size 59.

My version of Matplotlib is 3.1.3
Full error:

Traceback (most recent call last):

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/axes/_axes.py", line 4284, in _parse_scatter_color_args
    colors = mcolors.to_rgba_array(c)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/colors.py", line 294, in to_rgba_array
    result[i] = to_rgba(cc, alpha)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/colors.py", line 177, in to_rgba
    rgba = _to_rgba_no_colorcycle(c, alpha)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/colors.py", line 240, in _to_rgba_no_colorcycle
    raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))

ValueError: Invalid RGBA argument: 1


During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/Users/Python Files/multiclass.py", line 54, in <module>
    c=y_fruits_2d, cmap=cmap_fruits, edgecolor = 'black', alpha=.7)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/pyplot.py", line 2848, in scatter
    None else {}), **kwargs)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/__init__.py", line 1599, in inner
    return func(ax, *map(sanitize_sequence, args), **kwargs)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/axes/_axes.py", line 4453, in scatter
    get_next_color_func=self._get_patches_for_fill.get_next_color)

  File "/opt/anaconda3/lib/python3.7/site-packages/matplotlib/axes/_axes.py", line 4297, in _parse_scatter_color_args
    .format(nc=n_elem, xs=xsize, ys=ysize)

ValueError: 'c' argument has 59 elements, which is not acceptable for use with 'x' with size 59, 'y' with size 59.

I've fixed it though -- changed Y to Y.values.reshape(Y.shape[0])

jklymak closed this as completed Sep 21, 2017

ImportanceOfBeingErnest mentioned this issue Jun 4, 2018

Passing an incorrectly sized colour list to scatter should raise a relevant error #11373

Closed

developerpawandeep mentioned this issue Feb 19, 2020

@sabyagunnersya I try both (n,1) and (n,). Both of them are not working! Is there any other solution? Thanks! #16554

Closed

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Passing an incorrectly sized colour list to scatter should raise a relevant error #9209

Passing an incorrectly sized colour list to scatter should raise a relevant error #9209

MatthewJA commented Sep 21, 2017

jklymak commented Sep 21, 2017 •

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jklymak commented Sep 21, 2017 •

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jklymak commented Sep 21, 2017

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PorkShoulderHolder commented Feb 22, 2019

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sskgp commented Jun 18, 2019

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weihuaguo commented Oct 4, 2019

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TTitcombe commented Nov 19, 2019

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runnholm commented Nov 26, 2019

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sorenwacker commented Jun 2, 2020

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tacaswell commented Jun 2, 2020

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ngmaihuong commented Aug 10, 2020 •

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Passing an incorrectly sized colour list to scatter should raise a relevant error #9209

Passing an incorrectly sized colour list to scatter should raise a relevant error #9209

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