Manipulate Tick Labels On A Colorbar

I want to access the tick labels on my matplotlib colobar, so that I can manipulate them. My starting labels may be [-2,-1,0,1,2] for example. I have used: locs,oldlabels = plt.xti

Solution 1:

If your data is not confined to [0,1], I'd recommend using a norm when you pass the data to the colormap instead of changing the data and relabeling the colorbar: http://matplotlib.org/api/cm_api.html?highlight=norm%20colormap#matplotlib.cm.ScalarMappable.norm

However, you can relabel the colorbar by manipulating the underlying axis directly:

import numpy as np
import pylab as plt

A = np.random.random((10,10))

plt.subplot(121)
plt.imshow(A,interpolation='nearest')

cb = plt.colorbar()
oldlabels = cb.ax.get_yticklabels()
print(map(lambda x: x.get_text(),oldlabels))
newlabels = map(lambda x: str(2 * float(x.get_text())), oldlabels)
print(newlabels)
cb.ax.set_yticklabels(newlabels)
plt.show()

oh, and now I find the matplotlib gallery example, nearly the same: http://matplotlib.org/examples/pylab_examples/colorbar_tick_labelling_demo.html