How to efficiently create a line plot with connected horizontal lines per data point?

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I want to create a plot like this: Connected horizontal line plot

I know how to create horizontal lines in Matplotlib, and I see a way of creating many short horizontal lines and to connect them with short vertical lines, but I have the intuition that a better way is possible.

I have tried this code myself:

import matplotlib.pyplot as plt
y = [1, 1, 3, 3, 6, 6]
x = [1, 2, 2, 3, 3, 4]

plt.plot(x, y)
plt.show()

It produces this plot.

It has the basics of what I want, but since I have data per month, creating a plot like this requires some awkward data manipulation.

Lastly, I also thought of creating a bar plot which only show the top line of the bar, which would nicely create the horizontal lines, but they would not be connected.

Thanks in advance for your help!

matplotlib python
1 Answers

You initial intuition was correct, you can generate a list of the successive points with simple numpy array reshaping:

import numpy as np

x = np.array([0,1,2,3,4,5,6,7,8])
y = np.array([1,2,3,2,5,4,2,0,2])

x2 = np.c_[x-0.5,x+0.5].ravel()
y2 = np.c_[y,y].ravel()

plt.plot(x2, y2)

That said, this is all automated by matplotlib.pyplot.step, it has a where parameter to define the alignment (for example on the mid point):

plt.step(x, y, where='mid')

output:

step plot

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