To move the spines to the center of the plot, we need to remove two spines, making them hidden (set color to none). After that, we move two others to coordinate (0,0). The coordinates are specified in data space coordinates.

The following code shows how to do this:

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-np.pi, np.pi, 500, endpoint=True)
y = np.sin(x)

plt.plot(x, y)

ax = plt.gca()

# hide two spines
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')

# move bottom and left spine to 0,0
ax.spines['bottom'].set_position(('data',0))
ax.spines['left'].set_position(('data',0))

# move ticks positions
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

plt.show()

This is what the plot will look like:

This code is dependent on the plot that is drawn because we are moving spines to the location (0, 0) and are plotting a sine function on the interval where (0, 0) is in the middle of the plot.

Nevertheless, this demonstrated how to move spines to a particular location and how to get rid of spines we don't want to show.

Furthermore, spines can be limited to end where the data ends (for example, using a set_smart_bounds(True) call). In this case, matplotlib tries to set bounds in a sophisticated way (for example, to handle inverted limits or to clip line to view if data extends past view).