One of the most important aspects of computing with data is the ability to manipulate it to enable subsequent analysis and visualization. R offers a wide range of tools for this purpose. Data from any source, be it flat files or databases, can be loaded into R and this will allow you to manipulate data format into structures that support reproducible and convenient data analysis. This practical, example-oriented guide aims to discuss the split-apply-combine strategy in data manipulation, which is a faster data manipulation approach. After reading this book, you will not only be able to efficiently manage and check the validity of your datasets with the split-apply-combine strategy, but you will also learn to handle larger datasets.
This book starts with describing the R objects mode and class, and then highlights different R data types, explaining their basic operations. You will focus on group-wise data manipulation with the split-apply-combine strategy, supported by specific examples. You will also learn to efficiently handle date, string, and factor variables along with different layouts of datasets using the reshape2 package. You will learn to use plyr effectively for data manipulation, truncating and rounding data, simulating data sets, as well as character manipulation. Finally you will get acquainted with using R with SQL databases.