I have created a subplots grid without any spaces between the subplots, with shared x,y-axes. I only show the ticks and labels for the outer subplots. The problem is that the tick numbers overlap at the borders of the subplots. With MaxNLocator, I can remove the upper or lower ticks, but only for all plots at once.

Question: How can I keep the highest tick only for certain plots (in this case x=2.0 only in the bottom right subplot, and y=3 only in the top left subplot)? Why does my conditional setting of ticks for certain subplots fail?

Code:

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import MaxNLocatornumPlotsY = 3
numPlotsX = 3
f, ax_grid = plt.subplots(numPlotsY,numPlotsX,sharex=True,sharey=True)A = np.arange(numPlotsY)+1.0
phi = np.arange(numPlotsX)
x = np.linspace(0,2.0,100)
fontsize = 18for y_i in range(0,numPlotsY):for x_i in range(0,numPlotsX):y = A[y_i]*np.sin(x*np.pi + phi[x_i])ax = ax_grid[y_i,x_i]ax.plot(x,y,lw=2.0)if x_i == 0:ax.set_ylabel(r'$y$', fontsize=fontsize)if y_i == numPlotsY-1:############################ Why doesn't this work?! ############################if x_i != numPlotsX-1:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='upper'))else:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune=None))ax.set_xlabel(r'$x/\pi$', fontsize=fontsize)if y_i == 0:ax.set_title(r'$\phi=%s$' % phi[x_i], fontsize=fontsize)if x_i == numPlotsX-1:ax.annotate(r'$A=%d$' % A[x_i], xy=(1.1,0.5), rotation=90,ha='center',va='center',xycoords='axes fraction', fontsize=fontsize)f.subplots_adjust(wspace=0,hspace=0)
plt.suptitle(r'$A\cdot\sin\left(2\pi x + \phi\right)$',fontsize=18)
plt.show()

As @AndrasDeak pointed out, I cannot modify individual subplot ticks as long as I have set sharex=True,sharey=True. The solution is to set them to false

f, ax_grid = plt.subplots(numPlotsY,numPlotsX,sharex=False,sharey=False)

and changing the conditional statements from my original post to:

# If left-most column:  Remove all overlapping y-ticks
# Else:                 Remove all ticks
if x_i == 0:ax.set_ylabel(r'$y$', fontsize=fontsize)# If top left subplot:      Remove bottom y-tick# If bottom left subplot:   Remove top y-tick# Else:                     Remove top and bottom y-ticksif y_i == 0:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='lower'))elif y_i == numPlotsY-1:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='upper'))else:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='both'))
else:ax.yaxis.set_ticks([])# If bottom row:    Remove all overlapping x-ticks
# Else:             Remove all ticks
if y_i == numPlotsY-1:# If bottom left subplot:   Remove right x-tick# If bottom right subplot:  Remove top left x-tick# Else:                     Remove left and right x-ticksif x_i == 0:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='upper'))elif x_i == numPlotsX-1:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='lower'))else:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='both'))
else:ax.xaxis.set_ticks([])

Not the most elegant result, but it demonstrates how to manipulate only the overlapping ticks:

Full code for anyone interested:

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import MaxNLocatornumPlotsY = 3
numPlotsX = 3
f, ax_grid = plt.subplots(numPlotsY,numPlotsX,sharex=False,sharey=False)A = np.arange(numPlotsY)+1.0
phi = np.arange(numPlotsX)
x = np.linspace(0,2.0,100)
fontsize = 18for y_i in range(0,numPlotsY):for x_i in range(0,numPlotsX):y = A[y_i]*np.sin(x*np.pi + phi[x_i])ax = ax_grid[y_i,x_i]ax.plot(x,y,lw=2.0)# If left-most column:  Remove all overlapping y-ticks# Else:                 Remove all ticksif x_i == 0:ax.set_ylabel(r'$y$', fontsize=fontsize)# If top left subplot:      Remove bottom y-tick# If bottom left subplot:   Remove top y-tick# Else:                     Remove top and bottom y-ticksif y_i == 0:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='lower'))elif y_i == numPlotsY-1:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='upper'))else:nbins = len(ax.get_yticklabels())ax.yaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='both'))else:ax.yaxis.set_ticks([])# If bottom row:    Remove all overlapping x-ticks# Else:             Remove all ticksif y_i == numPlotsY-1:# If bottom left subplot:   Remove right x-tick# If bottom right subplot:  Remove top left x-tick# Else:                     Remove left and right x-ticksif x_i == 0:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='upper'))elif x_i == numPlotsX-1:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='lower'))else:nbins = len(ax.get_xticklabels())ax.xaxis.set_major_locator(MaxNLocator(nbins=nbins,prune='both'))else:ax.xaxis.set_ticks([])if y_i == 0:ax.set_title(r'$\phi=%s$' % phi[x_i], fontsize=fontsize)if x_i == numPlotsX-1:ax.annotate(r'$A=%d$' % A[x_i], xy=(1.1,0.5), rotation=90,ha='center',va='center',xycoords='axes fraction', fontsize=fontsize)f.subplots_adjust(wspace=0,hspace=0)
plt.suptitle(r'$A\cdot\sin\left(2\pi x + \phi\right)$',fontsize=18)
plt.show()