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Machine Learning with Swift

You're reading from  Machine Learning with Swift

Product type Book
Published in Feb 2018
Publisher Packt
ISBN-13 9781787121515
Pages 378 pages
Edition 1st Edition
Languages
Authors (3):
Jojo Moolayil Jojo Moolayil
Profile icon Jojo Moolayil
Alexander Sosnovshchenko Alexander Sosnovshchenko
Profile icon Alexander Sosnovshchenko
Oleksandr Baiev Oleksandr Baiev
View More author details

Table of Contents (18) Chapters

Title Page
Packt Upsell
Contributors
Preface
Getting Started with Machine Learning Classification – Decision Tree Learning K-Nearest Neighbors Classifier K-Means Clustering Association Rule Learning Linear Regression and Gradient Descent Linear Classifier and Logistic Regression Neural Networks Convolutional Neural Networks Natural Language Processing Machine Learning Libraries Optimizing Neural Networks for Mobile Devices Best Practices Index

Exploratory data analysis


First, we want to see how many individuals of each class we have. This is important, because if the class distribution is very imbalanced (like 1 to 100, for example), we will have problems training our classification models. You can get data frame columns via the dot notation. For example, df.label will return you the label column as a new data frame. The data frame class has all kinds of useful methods for calculating the summary statistics. The value_counts() method returns the counts of each element type in the data frame:

In []: 
df.label.value_counts() 
Out[]: 
platyhog       520 
rabbosaurus    480 
Name: label, dtype: int64 

The class distribution looks okay for our purposes. Now let's explore the features.

We need to group our data by classes, and calculate feature statistics separately to see the difference between the creature classes. This can be done using the groupby() method. It takes the label of the column by which you want to group your data:

In [...
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