> #创建数组
> a1 <- c("A1","A2")
> a2 <- c("B1","B2","B3")
> a3 <- c("C1","C2","C3","C4")
> z <- array(1:24,c(2,3,4),dimnames = list(a1,a2,a3))
> z
, , C1
B1 B2 B3
A1 1 3 5
A2 2 4 6
, , C2
B1 B2 B3
A1 7 9 11
A2 8 10 12
, , C3
B1 B2 B3
A1 13 15 17
A2 14 16 18
, , C4
B1 B2 B3
A1 19 21 23
A2 20 22 24
> #创建数据框以及使用
>
> patinentID <- c(1,2,3,4)
> age <- c(25,34,28,52)
> diabetes <- c("data1","data2","data1","data1")
> status <- c("Poor","Improved","Excellent","Poor")
> patientdata <- data.frame(patinentID,age,diabetes,status)
> patientdata
patinentID age diabetes status
1 1 25 data1 Poor
2 2 34 data2 Improved
3 3 28 data1 Excellent
4 4 52 data1 Poor
> #选取数据框元素
>
> patientdata[1:2]
patinentID age
1 1 25
2 2 34
3 3 28
4 4 52
> patientdata[c("diabetes","status")]
diabetes status
1 data1 Poor
2 data2 Improved
3 data1 Excellent
4 data1 Poor
> patientdata$age
[1] 25 34 28 52
