Book Image

R Data Analysis Cookbook - Second Edition

By : Kuntal Ganguly, Shanthi Viswanathan, Viswa Viswanathan
Book Image

R Data Analysis Cookbook - Second Edition

By: Kuntal Ganguly, Shanthi Viswanathan, Viswa Viswanathan

Overview of this book

Data analytics with R has emerged as a very important focus for organizations of all kinds. R enables even those with only an intuitive grasp of the underlying concepts, without a deep mathematical background, to unleash powerful and detailed examinations of their data. This book will show you how you can put your data analysis skills in R to practical use, with recipes catering to the basic as well as advanced data analysis tasks. Right from acquiring your data and preparing it for analysis to the more complex data analysis techniques, the book will show you how you can implement each technique in the best possible manner. You will also visualize your data using the popular R packages like ggplot2 and gain hidden insights from it. Starting with implementing the basic data analysis concepts like handling your data to creating basic plots, you will master the more advanced data analysis techniques like performing cluster analysis, and generating effective analysis reports and visualizations. Throughout the book, you will get to know the common problems and obstacles you might encounter while implementing each of the data analysis techniques in R, with ways to overcoming them in the easiest possible way. By the end of this book, you will have all the knowledge you need to become an expert in data analysis with R, and put your skills to test in real-world scenarios.
Table of Contents (14 chapters)

Removing duplicate cases

We sometimes end up with duplicate cases in our datasets and want to retain only one among them.

Getting ready

Create a sample data frame:

> salary <- c(20000, 30000, 25000, 40000, 30000, 34000, 30000) 
> family.size <- c(4,3,2,2,3,4,3)
> car <- c("Luxury", "Compact", "Midsize", "Luxury", "Compact", "Compact", "Compact")
> prospect <- data.frame(salary, family.size, car)

How to do it...

The unique() function can do the job. It takes a vector or data frame as an argument and returns an object of the same type as its argument, but with duplicates removed.

Remove duplicates to get unique values:

> prospect.cleaned <- unique(prospect) 
> nrow(prospect)
[1] 7
> nrow(prospect.cleaned)
[1] 5

How it works...

The unique() function takes a vector or data frame as an argument and returns a similar object with the duplicate eliminated. It returns the non-duplicated cases as is. For repeated cases, the unique() function includes one copy in the returned result.

There's more...

Sometimes we just want to identify the duplicated values without necessarily removing them.

Identifying duplicates without deleting them

For this, use the duplicated() function:

> duplicated(prospect) 

From the data, we know that cases 2, 5, and 7 are duplicates. Note that only cases 5 and 7 are shown as duplicates. In the first occurrence, case 2 is not flagged as a duplicate.

To list the duplicate cases, use the following code:

> prospect[duplicated(prospect), ] 

salary family.size car
5 30000 3 Compact
7 30000 3 Compact