matplotlib: how to decrease density of tick labels in subplots?

Question

I'm looking to decrease density of tick labels on differing subplot

import pandas as pd import matplotlib.pyplot as plt import matplotlib.gridspec as gridspec from StringIO import StringIO data = """\     a   b   c   d z   54.65   6.27    19.53   4.54 w   -1.27   4.41    11.74   3.06 d   5.51    3.39    22.98   2.29 t   76284.53    -0.20   28394.93    0.28 """ df = pd.read_csv(StringIO(data), sep='\s+') gs = gridspec.GridSpec(3, 1,height_ratios=[1,1,4] ) ax0 = plt.subplot(gs[0]) ax1 = plt.subplot(gs[1]) ax2 = plt.subplot(gs[2]) df.plot(kind='bar', ax=ax0,color=('Blue','DeepSkyBlue','Red','DarkOrange')) df.plot(kind='bar', ax=ax1,color=('Blue','DeepSkyBlue','Red','DarkOrange')) df.plot(kind='bar', ax=ax2,color=('Blue','DeepSkyBlue','Red','DarkOrange'),rot=45) ax0.set_ylim(69998, 78000) ax1.set_ylim(19998, 29998) ax2.set_ylim(-2, 28) ax0.legend().set_visible(False) ax1.legend().set_visible(False) ax2.legend().set_visible(False) ax0.spines['bottom'].set_visible(False) ax1.spines['bottom'].set_visible(False) ax1.spines['top'].set_visible(False) ax2.spines['top'].set_visible(False) ax0.xaxis.set_ticks_position('none') ax1.xaxis.set_ticks_position('none') ax0.xaxis.set_label_position('top') ax1.xaxis.set_label_position('top') ax0.tick_params(labeltop='off') ax1.tick_params(labeltop='off', pad=15) ax2.tick_params(pad=15) ax2.xaxis.tick_bottom() d = .015 kwargs = dict(transform=ax0.transAxes, color='k', clip_on=False) ax0.plot((-d,+d),(-d,+d), **kwargs) ax0.plot((1-d,1+d),(-d,+d), **kwargs) kwargs.update(transform=ax1.transAxes) ax1.plot((-d,+d),(1-d,1+d), **kwargs) ax1.plot((1-d,1+d),(1-d,1+d), **kwargs) ax1.plot((-d,+d),(-d,+d), **kwargs) ax1.plot((1-d,1+d),(-d,+d), **kwargs) kwargs.update(transform=ax2.transAxes) ax1.plot((-d,+d),(1-d/4,1+d/4), **kwargs) ax1.plot((1-d,1+d),(1-d/4,1+d/4), **kwargs) plt.show() 

which results in

I would like to decrease tick labels in the two upper subplots. How to do that ? Thanks.

Bonus: 1) how to get rid of the dotted line on y=0 at the basis of the bars? 2) how to get rid of x-trick label between subplot 0 and 1? 3) how to set the back of the plot to transparency? (see the right-bottom broken y-axis line that disappears behind the back of the plot)

Answer 1

A general approach is to tell matplotlib the desired number of ticks:

plt.locator_params(nbins=10) 

Edit by comments from @Daniel Power: to change for a single axis (e.g. 'x') on an axis, use:

ax.locator_params(nbins=10, axis='x') 

Answer 2

An improvement over the approach suggestion by Aman is the following:

import matplotlib.pyplot as plt  fig = plt.figure() ax = fig.add_subplot(1, 1, 1)  # ... plot some things ...  # Find at most 101 ticks on the y-axis at 'nice' locations max_yticks = 100 yloc = plt.MaxNLocator(max_yticks) ax.yaxis.set_major_locator(yloc)  plt.show() 

Hope this helps.