Book Image

Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

By : Steven Lawrence Fernandes, Tim Cox
Book Image

Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

By: Steven Lawrence Fernandes, Tim Cox

Overview of this book

Raspberry Pi 3 Cookbook for Python Programmers – Third Edition begins by guiding you through setting up Raspberry Pi 3, performing tasks using Python 3.6, and introducing the first steps to interface with electronics. As you work through each chapter, you will build your skills and apply them as you progress. You will learn how to build text classifiers, predict sentiments in words, develop applications using the popular Tkinter library, and create games by controlling graphics on your screen. You will harness the power of a built in graphics processor using Pi3D to generate your own high-quality 3D graphics and environments. You will understand how to connect Raspberry Pi’s hardware pins directly to control electronics, from switching on LEDs and responding to push buttons to driving motors and servos. Get to grips with monitoring sensors to gather real-life data, using it to control other devices, and viewing the results over the internet. You will apply what you have learned by creating your own Pi-Rover or Pi-Hexipod robots. You will also learn about sentiment analysis, face recognition techniques, and building neural network modules for optical character recognition. Finally, you will learn to build movie recommendations system on Raspberry Pi 3.
Table of Contents (23 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Finding similar users in the dataset


Finding similar users in the dataset is a critical step in movie recommendations, and this process is explained next.

How to do it...

  1. We will create a new Python file and import the following packages:
import json 
import numpy as np 
from pearson _dist_score import pearson _dist_score 
 
  1. First, define a function for the input user that will find the similar users. For this, three arguments are needed: the number of similar users, the input user, and the database. Check whether the user is present in the database. If they are present, calculate the Pearson correlation score between the users present in the database and the input user:
# Finds a specified number of users who are similar to the input user 
  def search_similar_user (dataset, input_user, users_number): 
    if input_user not in dataset: 
      raiseTypeError('User ' + input_user + ' not present in the dataset') 
      # Calculate Pearson scores for all the users 
      scores = np.array([[x,...