Handling and Processing Strings in R
Posted on September 22, 2013
Handling and Processing Strings in R is an ebook dedicated to show you some introductory material to manipulate character strings in R.
Why this ebook?
Many years ago I decided to apply for a job in a company that developed data mining applications for big retailers. I was invited for an on-site visit and I went through the typical series of interviews with the members of the analytics team. Everything was going smoothly and I was enjoying all the conversations. Then it came turn to meet the computer scientist. After briefly describing his role in the team he started asking me a bunch of technical questions and tests. Although I was able to answer those questions related with statistics and multivariate analysis, I had a really hard time trying to answer a series of questions related with string manipulations.
I will remember my interview with that guy as one of the most embarrassing moments of my life. That day, the first thing I did when I went back home was to open my laptop, launch R, and start reproducing the tests I failed to solve. It didn't take me that much to get the right answers. Unfortunately, it was too late and the harm was already done. Needless to say I wasn't offered the job. That shocking experience showed me that I was not prepared for manipulating character strings. I felt so bad that I promised myself to learn the basics of strings manipulation and text processing. "Handling and Processing Strings in R" is one of the derived results of that old promise.
The content of this ebook is the byproduct of my experience working with character string data in R. It is based on my notes, scripts, projects, and uncountable days and nights in which I've been struggling with text data. Briefly, I've tried to document and organize several topics related with manipulating character strings.
Handling and Processing Strings in R in a nutshell
Although this is not a complete list of the topics covered in the manuscript, here are some of the functions that are discussed in the ebook:
character()creating a character vector
is.character()test character mode
as.character()convert as character
Printing related functions
cat()concatenate and print
sprintf()C-style string formatting
toString()convert to string objects
Basic String Manipulations
char()count number of characters
tolower()convert to lower case
toupper()convert to upper case
substring()substrings of a character vector
substr()substrings of a character vector
String Manipulations with
str_length()number of characters
word()extract words from a sentence
Functions for Regular Expressions