The Essential R Reference

Mark Gardener

• Publisher: Wiley
• Year: 2012
• Print ISBN: 9781118391419
• eBook ISBN: 9781118391389
• Edition: 1
• Topic: Computer Science
• Subtopic: Computer Science General
• Index: Computer Science

An essential library of basic commands you can copy and paste into R

The powerful and open-source statistical programming language R is rapidly growing in popularity, but it requires that you type in commands at the keyboard rather than use a mouse, so you have to learn the language of R. But there is a shortcut, and that's where this unique book comes in. A companion book to Visualize This: The FlowingData Guide to Design, Visualization, and Statistics, this practical reference is a library of basic R commands that you can copy and paste into R to perform many types of statistical analyses.

Whether you're in technology, science, medicine, business, or engineering, you can quickly turn to your topic in this handy book and find the commands you need.

• Comprehensive command reference for the R programming language and a companion book to Visualize This: The FlowingData Guide to Design, Visualization, and Statistics
• Combines elements of a dictionary, glossary, and thesaurus for the R language
• Provides easy accessibility to the commands you need, by topic, which you can cut and paste into R as needed
• Covers getting, saving, examining, and manipulating data; statistical test and math; and all the things you can do with graphs
• Also includes a collection of utilities that you'll find useful

Simplify the complex statistical R programming language with The Essential R Reference.

.

Theme 1: Data

R is an object-oriented language; that means that it deals with named objects. Most often these objects are the data that you are analyzing. This theme deals with making, getting, saving, examining, and manipulating data objects.

Topics in this Theme

• Data Types
• Creating Data
• Importing Data
• Saving Data
• Viewing Data
• Summarizing Data
• Distribution of Data

Commands in this Theme:

[]

$

addmargins

aggregate

apply

array

as.data.frame

as.xxxx

attach

attr

attributes

c

case.names

cbind

character

class

colMeans

colnames

colSums

comment

cummax

cummin

cumprod

cumsum

data

data.frame

detach

dget

dim

dimnames

dir

dput

droplevels

dump

dxxxx

ecdf

factor

file.choose

fivenum

ftable

getwd

gl

head

inherits

integer

interaction

IQR

is

is.xxxx

lapply

length

levels

list

list.files

load

logical

ls

ls.str

lsf.str

mad

margin.table

matrix

mean

median

mode

names

NCOL

ncol

nlevels

NROW

nrow

numeric

objects

order

prop.table

ptukey

pxxxx

qtukey

quantile

qxxxx

range

rank

raw

rbind

read.csv

read.csv2

read.delim

read.delim2

read.spss

read.table

read.xls

read.xlsx

relevel

remove

reorder

resample

rep

rm

RNGkind

row.names

rowMeans

rownames

rowsum

rowSums

rxxxx

sample

sapply

save

save.image

scan

sd

search

seq

seq_along

seq_len

set.seed

setwd

sort

source

storage.mode

str

subset

sum

summary

sweep

table

tabulate

tail

tapply

ts

typeof

unclass

unlist

var

variable.names

vector

View

which

with

within

write

write.csv

write.csv2

write.table

xtabs

/Level1

Data Types

R recognizes many kinds of data, and these data can be in one of several forms. This topic shows you the commands relating to the kinds of data and how to switch objects from one form to another.

What’s In This Topic:

• Types of data

• The different types/forms of data objects
• Creating blank data objects

• Altering data types

• Switching data from one type to another

• Testing data types

• How to tell what type an object is

Types of Data

Data can exist as different types and forms. These have different properties and can be coerced from one type/form into another.

Command Name

array

An array is a multidimensional object.

start feature

---

SEE drop for reducing dimensions of arrays in Theme 2, “Math and Statistics: Matrix Math.”

---

end feature

Common Usage

array(data = NA, dim = length(data), dimnames = NULL)

Related Commands

as.array

is.array

dim

dimnames

drop

/Level1

Command Parameters

data = NA	A vector to be used to create the array. Other objects are coerced to form a vector before making the array.
dim = length(data)	The dimensions of the array as a vector. A vector of 2 sets row and column sizes, respectively.
dimnames = NULL	A list of names for each dimension of the array. The default, NULL, creates no names.

Examples

 ## Simple arrays > array(1:12) # Simple 12-item vector [1] 1 2 3 4 5 6 7 8 9 10 11 12 > array(1:12, dim = 12) # Set length explicitly [1] 1 2 3 4 5 6 7 8 9 10 11 12 > array(1:12, dim = 6) # Can set length to shorter than data [1] 1 2 3 4 5 6 > array(1:12, dim = 18) # Longer arrays recycle values to fill [1] 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 > array(1:24, dim = c(3, 4, 2)) # A 3-dimensional array , , 1 [,1] [,2] [,3] [,4] [1,] 1 4 7 10 [2,] 2 5 8 11 [3,] 3 6 9 12 , , 2 [,1] [,2] [,3] [,4] [1,] 13 16 19 22 [2,] 14 17 20 23...

Table of contents

• Cover
• Theme 1: Data
• Theme 2: Math and Statistics
• Theme 3: Graphics
• Theme 4: Utilities
• About the Author
• Introduction