Adjusting gridlines and ticks in matplotlib imshow

Question

I\'m trying to plot a matrix of values and would like to add gridlines to make the boundary between values clearer. Unfortunately, imshow decided to locate the tick marks in the

Answer 1

Try to shift axes ticks:

ax = plt.gca()
ax.set_xticks(np.arange(-.5, 10, 1))
ax.set_yticks(np.arange(-.5, 10, 1))
ax.set_xticklabels(np.arange(1, 12, 1))
ax.set_yticklabels(np.arange(1, 12, 1))