python - Cleanest way to hide every nth tick label in matplotlib colorbar?

49
votes

The labels on my horizontal colorbar are too close together and I don't want to reduce text size further:

cbar = plt.colorbar(shrink=0.8, orientation='horizontal', extend='both', pad=0.02)
cbar.ax.tick_params(labelsize=8)

horizontal colorbar with bad labels

I'd like to preserve all ticks, but remove every other label.

Most examples I've found pass a user-specified list of strings to cbar.set_ticklabels(). I'm looking for a general solution.

I played around with variations of

cbar.set_ticklabels(cbar.get_ticklabels()[::2])

and

cbar.ax.xaxis.set_major_locator(matplotlib.ticker.MaxNLocator(nbins=4))

but I haven't found the magic combination.

I know there must be a clean way to do this using a locator object.

4
pythonmatplotlib
Have you seen stackoverflow.com/questions/6485000/… ? The ticks on colorbar can be finicky (as there is a layer in there to make it easy to flip from a vertical to horizontal with out changing too much of your code (ideally just adding a kwarg)) - tacaswell
Yeah. That post was helpful, and I ran update_ticks() during my preliminary tests, but the final solution offered still involves user-defined lists for tick locs/labels. - David Shean
In case someone wanted to use pyplot directly instead of axes object: matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.xticks.html - M. Doosti Lakhani

4 Answers

71
votes

For loop the ticklabels, and call set_visible():

for label in cbar.ax.xaxis.get_ticklabels()[::2]:
    label.set_visible(False)
11
votes

One-liner for those who are into that!

n = 7  # Keeps every 7th label
[l.set_visible(False) for (i,l) in enumerate(ax.xaxis.get_ticklabels()) if i % n != 0]
11
votes

Just came across this thread, nice answers. I was looking for a way to hide every tick between the nth ticks. And found the enumerate function. So if anyone else is looking for something similar you can do it like this.

for index, label in enumerate(ax.xaxis.get_ticklabels()):
    if index % n != 0:
        label.set_visible(False)
5
votes

I use the following to show every 7th x label:

plt.scatter(x, y)
ax = plt.gca()
temp = ax.xaxis.get_ticklabels()
temp = list(set(temp) - set(temp[::7]))
for label in temp:
    label.set_visible(False)
plt.show()

It's pretty flexible, as you can do whatever you want instead of plt.scatter. Hope it helps.