Matplotlib plot only horizontal lines in step plot

Question

I am using matplotlib to plot some step functions from a dataframe

df[\'s1\'].plot(c=\'b\', drawstyle=\"steps-post\")
df[\'s2\'].plot(c=\'b\', drawstyle=\"st         


        

Answer 1

There is no built-in option to produce a step function without vertical lines as far as I can tell. But you may easily build one yourself. The following uses the fact that np.nan is not plotted and cuts the line. So adding np.nan in between the steps suppresses the vertical line.

import matplotlib.pyplot as plt
import numpy as np

def mystep(x,y, ax=None, where='post', **kwargs):
    assert where in ['post', 'pre']
    x = np.array(x)
    y = np.array(y)
    if where=='post': y_slice = y[:-1]
    if where=='pre': y_slice = y[1:]
    X = np.c_[x[:-1],x[1:],x[1:]]
    Y = np.c_[y_slice, y_slice, np.zeros_like(x[:-1])*np.nan]
    if not ax: ax=plt.gca()
    return ax.plot(X.flatten(), Y.flatten(), **kwargs)
    
x = [1,3,4,5,8,10,11]
y = [5,4,2,7,6,4,4]

mystep(x,y, color="crimson")

plt.show()