>>> """
========
Colorbar
========

Use `~.figure.Figure.colorbar` by specifying the mappable object (here
the `~.matplotlib.image.AxesImage` returned by `~.axes.Axes.imshow`)
and the axes to attach the colorbar to.
"""
... 
... import numpy as np
... import matplotlib.pyplot as plt
... 
... # setup some generic data
... N = 37
... x, y = np.mgrid[:N, :N]
... Z = (np.cos(x*0.2) + np.sin(y*0.3))
... 
... # mask out the negative and positive values, respectively
... Zpos = np.ma.masked_less(Z, 0)
... Zneg = np.ma.masked_greater(Z, 0)
... 
... fig, (ax1, ax2, ax3) = plt.subplots(figsize=(13, 3), ncols=3)
... 
... # plot just the positive data and save the
... # color "mappable" object returned by ax1.imshow
... pos = ax1.imshow(Zpos, cmap='Blues', interpolation='none')
... 
... # add the colorbar using the figure's method,
... # telling which mappable we're talking about and
... # which axes object it should be near
... fig.colorbar(pos, ax=ax1)
... 
... # repeat everything above for the negative data
... # you can specify location, anchor and shrink the colorbar
... neg = ax2.imshow(Zneg, cmap='Reds_r', interpolation='none')
... fig.colorbar(neg, ax=ax2, location='right', anchor=(0, 0.3), shrink=0.7)
... 
... # Plot both positive and negative values between +/- 1.2
... pos_neg_clipped = ax3.imshow(Z, cmap='RdBu', vmin=-1.2, vmax=1.2,
...                              interpolation='none')
... # Add minorticks on the colorbar to make it easy to read the
... # values off the colorbar.
... cbar = fig.colorbar(pos_neg_clipped, ax=ax3, extend='both')
... cbar.minorticks_on()
... plt.show()
... 
... #############################################################################
... #
... # .. admonition:: References
... #
... #    The use of the following functions, methods, classes and modules is shown
... #    in this example:
... #
... #    - `matplotlib.axes.Axes.imshow` / `matplotlib.pyplot.imshow`
... #    - `matplotlib.figure.Figure.colorbar` / `matplotlib.pyplot.colorbar`
... #    - `matplotlib.colorbar.Colorbar.minorticks_on`
... #    - `matplotlib.colorbar.Colorbar.minorticks_off`
...