Matplotlib

Matplotlib is a cross-platform, data visualization and graphical plotting library for Python and its numerical extension NumPy. As such, it offers a viable open source alternative to MATLAB. Developers can also use matplotlib’s APIs (Application Programming Interfaces) to embed plots in GUI applications.

A Python matplotlib script is structured so that a few lines of code are all that is required in most instances to generate a visual data plot. The matplotlib scripting layer overlays two APIs:

• The pyplot API is a hierarchy of Python code objects topped by?matplotlib.pyplot
• An OO (Object-Oriented) API collection of objects that can be assembled with greater flexibility than pyplot. This API provides?direct access to Matplotlib’s backend layers.??

Matplotlib and Pyplot in Python

The pyplot?API has a convenient MATLAB-style stateful interface. In fact, matplotlib was originally written as an open source alternative for MATLAB. The OO API and its interface is more customizable and powerful than pyplot, but considered more difficult to use. As a result, the pyplot interface is more commonly used, and is referred to by default in this article.?

Understanding matplotlib’s pyplot API is key to understanding how to work with plots:

• matplotlib.pyplot.figure: Figure?is the top-level container. It includes everything visualized in a plot including one or more?Axes.
• matplotlib.pyplot.axes:?Axes?contain most of the elements in a?plot:?Axis, Tick, Line2D, Text,?etc., and sets the coordinates. It is the area in which data is plotted. Axes include the X-Axis, Y-Axis, and possibly a Z-Axis, as well.