向量，即一维数组
a <- c("k","j","h","a","c");
a[3]
a[1:2]
a[c(1,3)]
a[5]
a[-1]
a[-2]
矩阵，二维数组
mymatrix <- matrix(1:10,nrow=5,ncol = 4)
mymatrix
mymatrix <- matrix(1:10,nrow=5,ncol = 4,byrow = TRUE)
mymatrix
x <- matrix(1:10,nrow = 2)
x
x[2,]
x[,2]
x[1,4]
x[1,c(1,5)]
数组
dim <- c("a1","a2")
dim1 <- c("a1","a2")
dim2 <- c("b1","b2","b3")
dim3 <- c("c1","c2","c3","c4")
z <- array(1:24,c(2,3,4),dimnames = list(dim1,dim2,dim3))
z
z[2,3,4]
数据框，可以放多种类型数据的二维数组
patientID <- c(1,2,3,4)
age <- c(33,22,3,3)
diabetes <- c("t2","t2","t3","t4")
status <- c("poor","Improved","excellent","poor")
patinetdata <- data.frame(patientID,age,diabetes,status)
patinetdata
patinetdata[1,2]
patinetdata[c("age","status")]
with(patinetdata,{age})
patinetdata <- data.frame(patientID,age,diabetes,status,row.names = patientID)
因子，类别或有序的一维数组
diabetes <- c("type","type2")
diabetes <- factor(diabetes)
diabetes
status <- factor(status,ordered = TRUE)
status <- factor(status,ordered = TRUE,levels = c("poor","Improved","excellent"))
status
patientID <- c(1,2,3,4)
age <- c(33,22,3,3)
diabetes <- c("t2","t2","t3","t4")
status <- c("poor","Improved","excellent","poor")
diabetes <- factor(diabetes)
status <- factor(status,ordered = TRUE)
patientdata <- data.frame(patientID,age,diabetes,status)
patientdata
str(patientdata)
summary(patientdata)
列表，一些对象的集合
g <- "my Fisrt List"
h <- c(25,26,18,19)
j <- matrix(1:10,nrow = 5)
k <- c("one","tow","STHEE")
mylist <- list(title=g,ages=h,j,k)
mylist
mylist[[2]]
mylist[["ages"]]
mylist$ages
mylist$ages[1]
patientdata
names(patientdata)
names(patientdata)[2] <- "agadfdfds"
patientdata
常用函数
length(patinetdata)
dim(patientdata)
str(patientdata)
class(patientdata)
mode(patientdata)
names(patientdata)
objects(patientdata)
head(patientdata)
tail(patinetdata)
ls()
