Reference

When using the library you will typically create Figure and Axes objects and call their methods to add content and modify the appearance.

Example: We create a Figure fig and Axes ax. Then we call methods on them to plot data, add axis labels and a figure title.

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(0, 4, 0.05)
y = np.sin(x*np.pi)

fig, ax = plt.subplots(figsize=(3,2), constrained_layout=True)
ax.plot(x, y)
ax.set_xlabel('t [s]')
ax.set_ylabel('S [V]')
ax.set_title('Sine wave')
fig.set_facecolor('lightsteelblue')

(Source code, png, pdf)

../_images/index-1.png

Toolkits

Toolkits are collections of application-specific functions that extend Matplotlib. The following toolkits are included:

Usage patterns

Below we describe several common approaches to plotting with Matplotlib.

The pyplot API

matplotlib.pyplot is a collection of functions that make Matplotlib work like MATLAB. Each pyplot function makes some change to a figure: e.g., creates a figure, creates a plotting area in a figure, plots some lines in a plotting area, decorates the plot with labels, etc.

pyplot is mainly intended for interactive plots and simple cases of programmatic plot generation.

Further reading:

The object-oriented API

At its core, Matplotlib is object-oriented. We recommend directly working with the objects, if you need more control and customization of your plots.

In many cases you will create a Figure and one or more Axes using pyplot.subplots and from then on only work on these objects. However, it's also possible to create Figures explicitly (e.g. when including them in GUI applications).

Further reading:

The pylab API (disapproved)

Warning

Since heavily importing into the global namespace may result in unexpected behavior, the use of pylab is strongly discouraged. Use matplotlib.pyplot instead.

pylab is a module that includes matplotlib.pyplot, numpy, numpy.fft, numpy.linalg, numpy.random, and some additional functions, all within a single namespace. Its original purpose was to mimic a MATLAB-like way of working by importing all functions into the global namespace. This is considered bad style nowadays.