- Basic Function
- rnorm(10)
- mean(abs(rnorm(100)) sd(rnorm(100))
- source("xxx.R")
- x<- c(1,2,4) q <- c(x,x,8)
- y # print out y
- q() # quit from command line
- seq(1,6,by=3) # 1 4
- seq(0,1,length.out=11) # 0.0,0.1,0.2,...0,9,1.0
- help(seq), ?seq, example(seq)
- Function
oddcount <- function(x) { # oddcount is function name
k <- 0
return (k)
}
- For statement
for (n in x) {
if(n%%2==1) k <- k+1
}
for (i in 1:length(x)) {
if(x[i]%%2==1) k <- k+1
}
- Data Structure:
- string: y<-"abc" mode(y) # "character"
- u<-paste("abc","def","e") # abc def e
- v<-strsplit(u," ") # split according to blanks
- matrix: m<-rbind(c(1,4),c(2,2)) # row bind
- m[1,2] # 4
- m[1,] # row 1
- m[,2] # column 2
- list: x<-list(u=2,v="abc")
- x$u # 2
- hn <- hist(Nile) # class
- print(hn)
- str(hn) # structure
- attr(,"class") # "histogram"
- d <- data.frame(list(kids=c("Jack","Jill"),ages=c(12,10)))
- d, d$age
- Regression Example
- examsquiz<-read.table("ExamsQuiz.txt",header=FALSE)
- class(examsquiz) # "data.frame"
- head(examsquiz) # less
- lma<-lm(examsquiz[,2] ~ examsquiz[,1]) # using col 1 to fit col 2
- lma<-lm(examsquiz$V2 ~ examsquiz$V1) # same as above
- attribute(lma), summary(lma) # like print, str
- lma, lma$coef
- lmb<-lm(examsquiz[,2] ~ examsquiz[,1] + examsquiz[,3]) # + is not concate symbol
