Matplotlib is a flexible, easily configurable package
EASY TO USE
Everything in matplotlib is organized in a hierarchy
A LOT OF TOOLS
Open-source and free
It supports a very wide variety of graphs and plots namely - histogram, bar charts, power spectra, error charts, etc.
The package is imported into the Python script easily
Matplotlib is a library in the Python programming language for data visualization of two-dimensional (2D) graphics. The resulting images can be used as illustrations in publications. Matplotlib is written and maintained primarily by John Hunter and is distributed under a BSD-like license. Images generated in various formats can be used in interactive graphics, in scientific publications, graphical user interface, web applications that require plotting.