More information at http://pyqtgraph.org.
PyQtGraph is a pure-python graphics and GUI library built on PyQt4 / PySide and numpy. It is intended for use in mathematics / scientific / engineering applications. Despite being written entirely in python, the library is very fast due to its heavy leverage of numpy for number crunching and Qt's GraphicsView framework for fast display.
Matplotlib is more or less the de-facto standard plotting library for python. If you are starting a new project and do not need any of the features specifically provided by pyqtgraph, you should start with matplotlib. It is much more mature, has an enormous user community, and produces very nice publication-quality graphics.
Reasons you might want to use pyqtgraph instead:
# It may be necessary to restart the Notebook Kernel, as # only one QApplication instance can exist at a time import numpy as np from PySide import QtGui, QtCore # this will force pyqtgraph to use PySide instead of PyQt4 import pyqtgraph as pg app = QtGui.QApplication() win = pg.GraphicsWindow(title="Title") win.resize(800, 600) p = win.addPlot(title="Plot") y = np.random.randn(100) p.plot(y, pen="b") p.plot(np.cumsum(y), pen="g") app.exec_() # for PySide only
# It may be necessary to restart the Notebook Kernel, as # only one QApplication instance can exist at a time import pyqtgraph.examples pyqtgraph.examples.run()