Book Image

NumPy Cookbook - Second Edition

By : Ivan Idris
Book Image

NumPy Cookbook - Second Edition

By: Ivan Idris

Overview of this book

<p>NumPy has the ability to give you speed and high productivity. High performance calculations can be done easily with clean and efficient code, and it allows you to execute complex algebraic and mathematical computations in no time.</p> <p>This book will give you a solid foundation in NumPy arrays and universal functions. Starting with the installation and configuration of IPython, you'll learn about advanced indexing and array concepts along with commonly used yet effective functions. You will then cover practical concepts such as image processing, special arrays, and universal functions. You will also learn about plotting with Matplotlib and the related SciPy project with the help of examples. At the end of the book, you will study how to explore atmospheric pressure and its related techniques. By the time you finish this book, you'll be able to write clean and fast code with NumPy.</p>
Table of Contents (19 chapters)
NumPy Cookbook Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Creating value initialized arrays with the full() and full_like() functions


The full() and full_like() functions are new additions to NumPy meant to facilitate initialization. Here's what the documentation says about them:

>>> help(np.full)
Return a new array of given shape and type, filled with `fill_value`.
>>> help(np.full_like)
Return a full array with the same shape and type as a given array.

How to do it...

Let's see how full() and full_like() function:

  1. Create a 1 by 2 array with full(), filled with the lucky number 7:

    print(np.full((1, 2), 7))

    Accordingly, we get the following array:

    array([[ 7.,  7.]])
    

    The array elements are floating-point numbers.

  2. Specify an integer data type, as follows:

    print(np.full((1, 2), 7, dtype=np.int))

    The output changes accordingly:

    array([[7, 7]])
    
  3. The full_like() function checks the metadata of an array and reuses it for the new array. For example, create an array using linspace(), and apply it as a template for the full_like() function:

    a =...