Plotting a horizontal line, y = constant in matplotlib

Question

I am using the following to plot a horizontal line in matplotlib:

axScatter.axhline(y=0.285987, xmin=-1.5, xmax=0.491, color='black', linestyle=':')

However, it is just ever so slightly out:

I'd rather have a function where y = 0.285987 between the x-range: -1.5 and ~0.72. Does anyone know how to plot a line without using axhline ?

Answer 1

axhline xmin and xmax are to given in the axes coordinates (so that 0.5 is the middle of the axes). If you want to have a exact line in data coordinates you could just use plot:

x = [-1.5, 0.72]
y = [0.285987, 0.285987]
ax.plot(x, y)