How to overplot a line on a scatter plot in python?

Question

I have two vectors of data and I\'ve put them into matplotlib.scatter(). Now I\'d like to over plot a linear fit to these data. How would I do this? I\'ve tried

Answer 1

A one-line version of this excellent answer to plot the line of best fit is:

plt.plot(np.unique(x), np.poly1d(np.polyfit(x, y, 1))(np.unique(x)))

Using np.unique(x) instead of x handles the case where x isn't sorted or has duplicate values.

The call to poly1d is an alternative to writing out m*x + b like in this other excellent answer.