RCode from Devin Flawd

Place to list common codes and explanations for worksheet


Extra stuff

Environment
help() # type any function to pull up the documentation
install.packages() # install an R package, can also use Tools -> Install Packages? on the menu bar
library(), require() # enable or activate R packages that have already been installed
rm() # remove an object
ls() # list all objects currently stored in the R environment
View() # open a separate tab to view a data frame as a spreadsheet
names() # retrieve or assign names to an object
na.rm() # remove NA values from an object
str() # return the string of an object (class type and values)
class() # return the class type of an object

Input and Display
DATAFRAME <- read.delim("C:/R/Examples/Length.txt", sep=??, header=TRUE) # 
DATAFRAME <- read.csv(file.choose()) # 
newframe <- x$columnname # assign a certain column (?columnname?) from data frame ?x? to a new data frame
*Personally I never use attach()/detach()*

Vectors and Matrices
a <- c(0,1,2) # assign (c)oncatenated objects to ?a? as a vector (in this case, of length 3)
> a
> 0 1 2
b <- c(3:5) # assign (c)oncatenated all objects between first and last objects specified (x:y)
> b
> 3 4 5
c <- c(a, b) # assign (c)oncatenated objects to ?c? as a vector of all objects
> c
> 0 1 2 3 4 5
cbind() # bind objects by column
> cbind(a, b)
> a b
  0 3
  1 4
  2 5
rbind() # bind objects by row
> rbind(a, b)
> a 0 1 2
  b 3 4 5

Basic Functions
mean() # return the mean of an object
var() # return the variance of an object
sd() # return the standard deviation of an object
sum() # return the sum of all values or objects
tapply()
summary()

d = density
p = cumulative distribution function
r = random
q = quantile

Probability
dbinom()
pbinom()
qbinom()
rbinom()
binom.test()

pnorm()
rnorm()
qnorm()
dnorm()

Plots
plot()
barplot()
boxplot()
hist()
lag.plot()
par()
qqnorm()
qqline()
resid()
fitted()

P-values
qt()
pt()
rt()
dt()
pchisq()
qchisq()
chisq.test()

Modeling and Stat Tests
lm()
t.test()
anova()