Matplotlib colorbar: __init__() got an unexpected keyword argument 'location'

Question

I was trying to plot a matplotlib colorbar to the left of my axis following the example given here: https://matplotlib.org/stable/gallery/axes_grid1/simple_colorbar.html#sphx-glr-gallery-axes-grid1-simple-colorbar-py

But as I wanted to have the colorbar on the left side of the axis, I tried:

import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.axes_grid1 import make_axes_locatable

fig, ax = plt.subplots(1, 1)

im = plt.imshow(np.arange(0, 100).reshape(10, 10))
ax.set_xticklabels([])
ax.set_yticklabels([])

divider = make_axes_locatable(ax)
cax = divider.append_axes("left", size="5%", pad=0.05)
colorbar = fig.colorbar(im, cax=cax, location='left')
colorbar.set_label('y label')

which gives me the following exception:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
 in 
     11 divider = make_axes_locatable(ax)
     12 cax = divider.append_axes("left", size = "5%", pad = 0.05)
---> 13 colorbar = fig.colorbar(im, cax = cax, location = 'left')
     14 colorbar.set_label('y label')
     15 

~\Anaconda3\envs\data-evaluation\lib\site-packages\matplotlib\figure.py in colorbar(self, mappable, cax, ax, use_gridspec, **kw)
   1171                              'panchor']
   1172         cb_kw = {k: v for k, v in kw.items() if k not in NON_COLORBAR_KEYS}
-> 1173         cb = cbar.Colorbar(cax, mappable, **cb_kw)
   1174 
   1175         self.sca(current_ax)

~\Anaconda3\envs\data-evaluation\lib\site-packages\matplotlib\colorbar.py in __init__(self, ax, mappable, **kwargs)
   1195             if isinstance(mappable, martist.Artist):
   1196                 _add_disjoint_kwargs(kwargs, alpha=mappable.get_alpha())
-> 1197             super().__init__(ax, **kwargs)
   1198 
   1199         mappable.colorbar = self

~\Anaconda3\envs\data-evaluation\lib\site-packages\matplotlib\_api\deprecation.py in wrapper(*args, **kwargs)
    469                 "parameter will become keyword-only %(removal)s.",
    470                 name=name, obj_type=f"parameter of {func.__name__}()")
--> 471         return func(*args, **kwargs)
    472 
    473     return wrapper

TypeError: __init__() got an unexpected keyword argument 'location'

Why is that? If I use:

colorbar = fig.colorbar(im, ax=ax, location='left')
colorbar.set_label('y label')

instead of divider, it seems to work, but the padding between the axis and colorbar is not as small as I want it.

user_2988730 · Answer

The example you cite does not use a location argument to colorbar:

colorbar = fig.colorbar(im, cax=cax)

That's because you are asking it to plot the colorbar in the new axes, which you already placed on the left with the statement cax = divider.append_axes("left", size="5%", pad=0.05). You can see that an empty axis is being generated for the colorbar before the error is thrown.

Keep in mind that doing it this way will invert the placement of your colorbar ticks and label:

You can avoid this by adding the following after the colorbar has been drawn (since the colorbar will undo the change):

cax.yaxis.tick_left()
cax.yaxis.set_label_position('left')

Matplotlib colorbar: init() got an unexpected keyword argument 'location'

1 Answers