R Command Symmary

  1. R Command Symmary
    1. Assignment
    2. Conditional
    3. Iteration, Flow control
    4. Arithmetic Operators
    5. Relational Operators
    6. Logical Operators
    7. Subscripts
      1. Subscript Forms
    8. Sequence and Repetition
    9. Arithmetic Operators and Functions
    10. Types
    11. I/O
      1. Data In
      2. Command File In
      3. Screen Output to File
      4. Write and Read Objects
      5. Make Things Available or Unavailable
    12. Reduction Operators
    13. Statistical Distributions
    14. Plotting
      1. Device-Specification
      2. Stopping Plotting
      3. Some Plot Parameters
      4. One-Dimension Plots
      5. Two-Dimension Plots
      6. Three-Dimension Plots
      7. 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")


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