Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Create a field called Processing Time that calculates the gap between OrderDate and ShippedDate using a function called Interval that formats the gap time."

A block of code is set as follows:

num (sum (Discount*SalesAmount)/sum (SalesAmount), '0.00%')

Any command-line input or output is written as follows:

install.packages("Rserve", lib = "C:\\R\\R-3.5.2\\library") 

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Creating new sheets is a breeze: to start from an existing sheet, just right-click and duplicate, or click the Create new button to start from a fresh blank sheet."