## Adding y=x to a matplotlib scatter plot if I haven’t kept track of all the data points that went in

You don’t need to know anything about your data per se. You can get away with what your matplotlib Axes object will tell you about the data. See below: import numpy as np import matplotlib.pyplot as plt # random data N = 37 x = np.random.normal(loc=3.5, scale=1.25, size=N) y = np.random.normal(loc=3.4, scale=1.5, size=N) c = …