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 – saving and loading a .mat file


If we start with NumPy arrays and decide to use said arrays within a MATLAB or Octave environment, the easiest thing to do is create a .mat file. We can, then, load the file within MATLAB or Octave. Let's go through the necessary steps:

  1. Create a NumPy array and call the savemat() function to create a .mat file. This function has two parameters: a file name and a dictionary containing variable names and values:

    a = np.arange(7)
    
    io.savemat("a.mat", {"array": a})
  2. Within a MATLAB or Octave environment, load the .mat file and check the stored array:

    octave-3.4.0:7> load a.mat
    octave-3.4.0:8> a
    
    octave-3.4.0:8> array
    array =
    
      0
      1
      2
      3
      4
      5
      6

What just happened?

We created a .mat file from NumPy code and loaded it within Octave. We checked the NumPy array that was created (see scipyio.py):

import numpy as np
from scipy import io

a = np.arange(7)

io.savemat("a.mat", {"array": a})

Pop quiz – loading .mat files

Q1. Which function loads...