R Command Symmary

R Command Symmary Assignment Conditional Iteration, Flow control Arithmetic Operators Relational Operators Logical Operators Subscripts Subscript Forms Sequence and Repetition Arithmetic Operators and Functions Types I/O Data In Command File In Screen Output to File Write and Read Objects Make Things Available or Unavailable Reduction Operators Statistical Distributions Plotting Device-Specification Stopping Plotting Some Plot Parameters One-Dimension Plots Two-Dimension Plots Three-Dimension Plots Multiple Plots Per Page

 

Assignment

expr <- expr

expr = expr

expr -> expr

 

Conditional

if ( expr ) expr

if ( expr ) expr else expr

 

Iteration, Flow control

repeat expr

while ( expr ) expr

for ( Name in expr ) expr

Flow

break

next

return ( expr )

( expr )

{ exprlist }

 

Arithmetic Operators

* Multiply

+ Add

- Subtract

/ Divide

^ Exponentiation

%% Remainder or modulo operator

%*% Matrix multiplication operator

%/% Integer divide

%c% crossproduct m1 %c% m2 is t(m1) %*% m2

%o% Outer Product

 

Relational Operators

!= Not-equal-to

< L ess-than

<= Less-than-or-equal-to

== Equal

> Greater-than

>= G reater-than-or-equal-to

 

Logical Operators

'!' Not

| Or (Use with arrays or matrices)

|| Shortcut Or (Don’t use with arrays or matrices)

& And (Use with arrays or matrices)

&& Shortcut And (Don’t use with arrays or matrices)

Above “shortcut” means that if the condition is not satisfied, the remaining parts of the expression are not even

evaluated. This is very useful if these parts don’t even make sense then, or are slow to execute.

 

Subscripts

[ ] Vector subscript

[[ ]] list subscript - can only identify a single element

$ Named component selection from a list

 

Subscript Forms

logical extracts or selects T component

positive numbers extracts or selects specified indices

negative numbers deletes specified indices

NA or out of range extends dimensions gives value NA

 

Sequence and Repetition

seq (from, to, by, length, along)

also : as in 1:10

rep(x, times, length)

 

Arithmetic Operators and Functions

abs(x)

acos(x)

acosh(x)

asin(x)

asinh(x)

atan(x)

atan(x, y)

atanh(x)

ceiling(x)

cos(x)

cosh(x)

exp(x)

floor(x)

gamma(x)

lgamma(x)

log(x, base=exp(1))

log10(x)

max(...) elementwise

min(...) elementwise

pmax(...) parallel

pmin(...) parallel

sin(x)

sinh(x)

sqrt(x)

tan(x)

tanh(x)

trunc(x)

 

Types

Can be used in as. and is. and (length)

array

category is, as only

character

complex

double

integer

list

logical

matrix

null is, as only

numeric

 

I/O

Data In

scan(file="", what=numeric(), n, sep, multi.line = F, flush = F, append = F)

Example: data <- matrix(scan("data.file"),ncol=5,byrow=T)

 

Command File In

source(file, local = F)

 

Screen Output to File

sink(file)

sink( ) restores output to screen

 

Write and Read Objects

dput(x, file) writes out object in S notation

dget(file)

write(t(matrix),file,ncol=ncol(matrix),append=FALSE)

data.dump(objnames, file=’filename’) objnames may be ’obj name’

or c(’name1’,’name2’,...)

data.restore(’filename’)

 

Make Things Available or Unavailable

assign("name", value, frame, where)

attach(file, pos=2)

detach(2)

library( )

library(help=section)

library(section, first=TRUE) make library’s functions take precedence

help(name="help", offline=F)

args(name="help")

 

Reduction Operators

all(...)

any(...)

length(x)

max(...)

mean(x, trim=0)

median(x)

min(...)

mode(x)

prod(...)

quantile(x, probs=c(0,.25,.5,.75,1))

sum(...)

var(x,y)

cor(x,y,trim=0)

 

Statistical Distributions

d(x,) density at x

p(x,) cumulative distn fn to x

q(p,) inverse cdf

r(n,) generates n random numbers from distn

Distribution Parameters Defaults

beta beta shape1, shape2 -, -

cauchy Cauchy loc, scale 0, 1

chisq chi-square df -

exp exponential - -

f F df1, df2 -, -

gamma Gamma shape -

lnorm log-normal mean, sd (of log) 0, 1

logis logistic loc, scale 0, 1

norm normal mean, sd 0, 1

stab stable index, skew -, 0

t Student’s t df -

unif uniform min, max 0, 1

 

Plotting

Device-Specification

postscript(file, command, horizontal=F, width, height, rasters, pointsize=14, font=1, preamble=ps.preamble, fonts=ps.fonts)

x11()

jpeg()

png()

quartz()

 

Stopping Plotting

graphics.off()

dev.off()

 

Some Plot Parameters

log=’<x|y|xy>’ Logarithmic axes

main=’title’

new= T forces addition to current plot

sub=’bottom title’

type=’<l|p|b|n>’ Line, points, both, none

lty=n Line type

pch=’.’ Plot character

xlab=’x-axis label’

ylab=’y-axis label’

xlim=c(xlo.value,xhi.value)

ylim=c(ylo.value,yhi.value)

 

One-Dimension Plots

barplot(height) #simple form

barplot(height, width, names, space=.2, inside=TRUE,

beside=FALSE, horiz=FALSE, legend, angle,

density, col, blocks=TRUE)

boxplot(..., range, width, varwidth=FALSE,

notch=FALSE, names, plot=TRUE)

hist(x, nclass, breaks, plot=TRUE, angle,

density, col, inside)

 

Two-Dimension Plots

lines(x, y, type="l")

points(x, y, type="p"))

matplot(x, y, type="p", lty=1:5, pch=, col=1:4)

matpoints(x, y, type="p", lty=1:5, pch=, col=1:4)

matlines(x, y, type="l", lty=1:5, pch=, col=1:4)

plot(x, y, type="p", log="")

abline(coef)

abline(a, b)

abline(reg)

abline(h=)

abline(v=)

qqplot(x, y, plot=TRUE)

qqnorm(x, datax=FALSE, plot=TRUE)

 

Three-Dimension Plots

contour(x, y, z, v, nint=5, add=FALSE, labex)

interp(x, y, z, xo, yo, ncp=0, extrap=FALSE)

persp(z, eye=c(-6,-8,5), ar=1)

 

Multiple Plots Per Page

par(mfrow=(nrow, ncol), oma=c(0, 0, 4, 0))

mtext(side=3, line=0, cex=2, outer=T,

"This is an Overall Title For the Page")