Fix Python – Confusion between numpy, scipy, matplotlib and pylab

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Question

Asked By – goFrendiAsgard

Numpy, scipy, matplotlib, and pylab are common terms among they who use python for scientific computation.

I just learn a bit about pylab, and I got confused.
Whenever I want to import numpy, I can always do:

import numpy as np

I just consider, that once I do

from pylab import *

the numpy will be imported as well (with np alias). So basically the second one does more things compared to the first one.

There are few things I want to ask:

  1. Is it right that pylab is just a wrapper for numpy, scipy and matplotlib?
  2. As np is the numpy alias in pylab, what is the scipy and matplotlib alias in pylab? (as far as I know, plt is alias of matplotlib.pyplot, but I don’t know the alias for the matplotlib itself)

Now we will see solution for issue: Confusion between numpy, scipy, matplotlib and pylab

Answer

  1. No, pylab is part of matplotlib (in matplotlib.pylab) and tries to give you a MatLab like environment. matplotlib has a number of dependencies, among them numpy which it imports under the common alias np. scipy is not a dependency of matplotlib.

  2. If you run ipython --pylab an automatic import will put all symbols from matplotlib.pylab into global scope. Like you wrote numpy gets imported under the np alias. Symbols from matplotlib are available under the mpl alias.

This question is answered By – Benjamin Bannier

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