Using Matplotlib's Step and Plot Functions

Introduction

Matplotlib is a plotting library for the Python programming language and its numerical mathematics extension NumPy. It provides an object-oriented API for embedding plots into applications using general-purpose GUI toolkits like Tkinter, wxPython, Qt, or GTK. Matplotlib was originally developed by John D. Hunter in 2003.

This tutorial will guide you on how to use the .step() and .plot() functions in Matplotlib.

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Skills Graph

Import necessary libraries

First, we need to import the necessary libraries, which are matplotlib.pyplot and numpy.

import matplotlib.pyplot as plt
import numpy as np

Create data for the plot

Next, let's create some data that we will use to plot. We will use the numpy.arange() function to create an array of values from 0 to 14 and store it in the variable x. We will also use the numpy.sin() function to create an array of values that are the sine of each value in x divided by 2, and store it in the variable y.

x = np.arange(14)
y = np.sin(x / 2)

Plot using .step()

We can use the .step() function to create piece-wise constant curves. The where parameter determines where the steps should be drawn. We will create three plots using different values for where.

plt.step(x, y + 2, label='pre (default)', where='pre')
plt.step(x, y + 1, label='mid', where='mid')
plt.step(x, y, label='post', where='post')
plt.legend()
plt.show()

The above code will create a plot with three piece-wise constant curves, each with a different value for where.

Plot using .plot()

We can achieve the same behavior as .step() by using the drawstyle parameter of the .plot() function. We will create three plots using different values for drawstyle.

plt.plot(x, y + 2, drawstyle='steps', label='steps (=steps-pre)')
plt.plot(x, y + 1, drawstyle='steps-mid', label='steps-mid')
plt.plot(x, y, drawstyle='steps-post', label='steps-post')
plt.legend()
plt.show()

The above code will create a plot with three piece-wise constant curves, each with a different value for drawstyle.

Summary

In this tutorial, we learned how to use the .step() and .plot() functions in Matplotlib to create piece-wise constant curves. We also learned how to use the where and drawstyle parameters to determine where the steps should be drawn.