python - 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')