Book Image

R for Data Science Cookbook (n)

By : Yu-Wei, Chiu (David Chiu)
Book Image

R for Data Science Cookbook (n)

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

This cookbook offers a range of data analysis samples in simple and straightforward R code, providing step-by-step resources and time-saving methods to help you solve data problems efficiently. The first section deals with how to create R functions to avoid the unnecessary duplication of code. You will learn how to prepare, process, and perform sophisticated ETL for heterogeneous data sources with R packages. An example of data manipulation is provided, illustrating how to use the “dplyr” and “data.table” packages to efficiently process larger data structures. We also focus on “ggplot2” and show you how to create advanced figures for data exploration. In addition, you will learn how to build an interactive report using the “ggvis” package. Later chapters offer insight into time series analysis on financial data, while there is detailed information on the hot topic of machine learning, including data classification, regression, clustering, association rule mining, and dimension reduction. By the end of this book, you will understand how to resolve issues and will be able to comfortably offer solutions to problems encountered while performing data analysis.
Table of Contents (19 chapters)
R for Data Science Cookbook
About the Author
About the Reviewer

Pruning redundant rules

Among generated rules, we sometimes find repeated or redundant rules (for instance, one rule is the super rule of another rule). In this recipe, we will show how to prune (or remove) repeated or redundant rules.

Getting ready

In this recipe, one has to have completed the previous recipe by generating rules and having these stored in a variable named rules.

How to do it…

Perform the following steps to prune redundant rules:

  1. First, you need to identify the redundant rules:

    > rules.sorted = sort(rules, by="lift")
    > subset.matrix = is.subset(rules.sorted, rules.sorted)
    > subset.matrix[lower.tri(subset.matrix, diag=T)] = NA
    > redundant = colSums(subset.matrix, na.rm=T) >= 1
  2. You can then remove the redundant rules:

    > rules.pruned = rules.sorted[!redundant]
    > inspect(rules.pruned)
      lhs                 rhs              support     confidence lift    
    1 {P0014252070}    => {P0014252066}    0.001321491 0.2704403  27.32874
    5 {P0014252055}    => {P0014252066...