Book Image

Time Series Analysis with Python Cookbook

By : Tarek A. Atwan
Book Image

Time Series Analysis with Python Cookbook

By: Tarek A. Atwan

Overview of this book

Time series data is everywhere, available at a high frequency and volume. It is complex and can contain noise, irregularities, and multiple patterns, making it crucial to be well-versed with the techniques covered in this book for data preparation, analysis, and forecasting. This book covers practical techniques for working with time series data, starting with ingesting time series data from various sources and formats, whether in private cloud storage, relational databases, non-relational databases, or specialized time series databases such as InfluxDB. Next, you’ll learn strategies for handling missing data, dealing with time zones and custom business days, and detecting anomalies using intuitive statistical methods, followed by more advanced unsupervised ML models. The book will also explore forecasting using classical statistical models such as Holt-Winters, SARIMA, and VAR. The recipes will present practical techniques for handling non-stationary data, using power transforms, ACF and PACF plots, and decomposing time series data with multiple seasonal patterns. Later, you’ll work with ML and DL models using TensorFlow and PyTorch. Finally, you’ll learn how to evaluate, compare, optimize models, and more using the recipes covered in the book.
Table of Contents (18 chapters)

Handling missing data with univariate imputation using pandas

Generally, there are two approaches to imputing missing data: univariate imputation and multivariate imputation. This recipe will explore univariate imputation techniques available in pandas.

In univariate imputation, you use non-missing values in a single variable (think a column or feature) to impute the missing values for that variable. For example, if you have a sales column in the dataset with some missing values, you can use a univariate imputation method to impute missing sales observations using average sales. Here, a single column (sales) was used to calculate the mean (from non-missing values) for imputation.

Some basic univariate imputation techniques include the following:

  • Imputing using the mean.
  • Imputing using the last observation forward (forward fill). This can be referred to as Last Observation Carried Forward (LOCF).
  • Imputing using the next observation backward (backward fill). This...