Subscription
0
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning

## You're reading fromPython Machine Learning (Wiley)

Product type Book
Published in Apr 2019
Publisher Wiley
ISBN-13 9781119545637
Pages 320 pages
Edition 1st Edition
Languages
Concepts
Author (1):
Wei-Meng Lee

1. Cover
2. Introduction
3. CHAPTER 1: Introduction to Machine Learning 4. CHAPTER 2: Extending Python Using NumPy 5. CHAPTER 3: Manipulating Tabular Data Using Pandas 6. CHAPTER 4: Data Visualization Using matplotlib 7. CHAPTER 5: Getting Started with Scikit‐learn for Machine Learning 8. CHAPTER 6: Supervised Learning—Linear Regression 9. CHAPTER 7: Supervised Learning—Classification Using Logistic Regression 10. CHAPTER 8: Supervised Learning—Classification Using Support Vector Machines 11. CHAPTER 9: Supervised Learning—Classification Using K‐Nearest Neighbors (KNN) 12. CHAPTER 10: Unsupervised Learning—Clustering Using K‐Means 13. CHAPTER 11: Using Azure Machine Learning Studio 14. CHAPTER 12: Deploying Machine Learning Models 15. Index

# Creating NumPy Arrays

Before using NumPy, you first need to import the NumPy package (you may use its conventional alias np if you prefer):

import numpy as np

The first way to make NumPy arrays is to create them intrinsically, using the functions built right into NumPy. First, you can use the arange() function to create an evenly spaced array with a given interval:

a1 = np.arange(10)        # creates a range from 0 to 9
print(a1)                 # [0 1 2 3 4 5 6 7 8 9]
print(a1.shape)           # (10,)

The preceding statement creates a rank 1 array (one‐dimensional) of ten elements. To get the shape of the array, use the shape property. Think of a1 as a 10×1 matrix.

You can also specify a step in the arange() function. The following code snippet inserts a step value of 2:

a2 = np.arange(0,10,2)    # creates a range from 0 to 9, step 2
print(a2)                 # [0 2 4 6 8]

To create an array of a specific size filled with 0s, use the zeros() function:

a3 = np.zeros(5...
The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at €18.99/month. Cancel anytime