Untitled

?c
x <- c("H", "I")
x <- c(1,2,3,4,5,6) # = x <- 1:6
x
x[2:4]
x[c(1,3,5)]
x[c(T, F, T)]
x[x>3]
x[2]^x[3]
x[2]%%x[3]
x[2]/x[3]

Ten=c("hi", "hello")	
Tuoi=c(19,29)
GioiTinh=c("Male", "Female")
ChieuCao=c(1.79, 1.56)

DuLieu <- data.frame(Ten, Tuoi, GioiTinh, ChieuCao) 

DuLieu
DuLieu$Ten

DuLieu[2]
DuLieu[,2]
DuLieu[2,]

y <- c(0,2,4,6,10,4)
y
x + y
x * y
exp(x)
length(x)
sort(y)
sort(y, decreasing=TRUE)
order(y)
y[order(y)] # = sort(y)
rev(y) # reverse
sum(y)

getwd()
setwd('E:/R lab')
data <- read.csv('E:/R lab/DataExcel.csv')
data
str(data)
?str
attach(data)
z <- data$T1
z <- T1
T1
dim(data)
# save(data, file="data.rda")
# dr = load("data.rda")

# Plot
TanSoKV <- table(KV)
pie(TanSoKV)

DanhGiaT1 <- T1
DanhGiaT1
DanhGiaT1[T1<5] <- "Kem"
DanhGiaT1[T1>=5 & T1<7] <- "Trung binh"
DanhGiaT1[T1>=7 & T1<8] <- "Kha"
DanhGiaT1[T1>=8] <- "Gioi"
DanhGiaT1
TanSoT1 <- table(DanhGiaT1)
pie(TanSoT1)

?barplot
barplot(TanSoT1)