Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Time for action – creating universal functions


We can create a ufunc from a Python function with the NumPy the frompyfunc() function as follows:

  1. Define a Python function that answers the ultimate question to the universe, existence, and the rest (it's from The Hitchhiker's Guide to the Galaxy, Douglas Adam, Pan Books, if you haven't read it, you can safely ignore this!):

    def ultimate_answer(a):

    So far, nothing special; we gave the function the name ultimate_answer() and defined one parameter, a.

  2. Create a result consisting of all zeros that has the same shape as a, with the zeros_like() function:

    result = np.zeros_like(a)
  3. Now, set the elements of the initialized array to the answer 42 and return the result. The complete function should appear as shown in the following code snippet. The flat attribute gives us access to a flat iterator that allows us to set the value of the array.

    def ultimate_answer(a):
       result = np.zeros_like(a)
       result.flat = 42
       return result
  4. Create a ufunc with frompyfunc...