Housekeeping and loading of necessary packages

First, clear out the workspace (after saving any R objects you will need later):

rm(list = ls())

Then, install the required packages:

install.packages("dplyr")
install.packages("wakefield")
install.packages("sqldf")
install.packages("RSQLite")

The convention in this book will be to specify a simple install.packages("packagename") instruction to install the necessary packages, followed by a library("packagename") to load them into memory. Once the required packages are installed, you can either comment them out, or replace the line with conditional installation code:

try(require(dplyr) || install.packages("dplyr"))

But this syntax may not work on all R installations and GUIs, so we will keep it simple, and explicitly specify install.package().

Now we will load the required packages into memory:

library(dplyr) 
library(wakefield) 
library(sqldf) 
library(RSQLite)