Matplotlib: How to force integer tick labels?

Question

My python script uses matplotlib to plot a 2D "heat map" of an x, y, z dataset. My x- and y-values represent amino acid residues in a protein and can therefore only be integers. When I zoom into the plot, it looks like this:

As I said, float values on the x-y axes do not make sense with my data and I therefore want it to look like this:

Any ideas how to achieve this? This is the code that generates the plot:

def plotDistanceMap(self):     # Read on x,y,z     x = self.currentGraph['xData']     y = self.currentGraph['yData']     X, Y = numpy.meshgrid(x, y)     Z = self.currentGraph['zData']     # Define colormap     cmap = colors.ListedColormap(['blue', 'green', 'orange', 'red'])     cmap.set_under('white')     cmap.set_over('white')     bounds = [1,15,50,80,100]     norm = colors.BoundaryNorm(bounds, cmap.N)     # Draw surface plot     img = self.axes.pcolor(X, Y, Z, cmap=cmap, norm=norm)     self.axes.set_xlim(x.min(), x.max())     self.axes.set_ylim(y.min(), y.max())     self.axes.set_xlabel(self.currentGraph['xTitle'])     self.axes.set_ylabel(self.currentGraph['yTitle'])     # Cosmetics     #matplotlib.rcParams.update({'font.size': 12})     xminorLocator = MultipleLocator(10)     yminorLocator = MultipleLocator(10)     self.axes.xaxis.set_minor_locator(xminorLocator)     self.axes.yaxis.set_minor_locator(yminorLocator)     self.axes.tick_params(direction='out', length=6, width=1)     self.axes.tick_params(which='minor', direction='out', length=3, width=1)     self.axes.xaxis.labelpad = 15     self.axes.yaxis.labelpad = 15     # Draw colorbar     colorbar = self.figure.colorbar(img, boundaries = [0,1,15,50,80,100],                                      spacing = 'proportional',                                     ticks = [15,50,80,100],                                      extend = 'both')     colorbar.ax.set_xlabel('Angstrom')     colorbar.ax.xaxis.set_label_position('top')     colorbar.ax.xaxis.labelpad = 20     self.figure.tight_layout()           self.canvas.draw() 

Answer 1

This should be simpler:

(from https://scivision.co/matplotlib-force-integer-labeling-of-axis/)

import matplotlib.pyplot as plt from matplotlib.ticker import MaxNLocator #... ax = plt.figure().gca() #... ax.xaxis.set_major_locator(MaxNLocator(integer=True))