數(shù)組(array)就是k維的數(shù)據(jù)表苟蹈，當(dāng)k=2時(shí)葵擎，數(shù)組就是矩陣(matrix).數(shù)組是矩陣的推廣.
- 數(shù)組的建立
一般采用函數(shù)
array(data = NA, dim = length(data), dimnames = NULL)
建立數(shù)組蜡豹，其中data為數(shù)據(jù)麸粮，dim為數(shù)組的維數(shù)，dimnames為數(shù)組維數(shù)的名稱镜廉。
#建立維數(shù)為(3,4,2)的數(shù)組
> data1<-array(1:24,dim=c(3,4,2))
> data1
, , 1
[,1] [,2] [,3] [,4]
[1,] 1 4 7 10
[2,] 2 5 8 11
[3,] 3 6 9 12
, , 2
[,1] [,2] [,3] [,4]
[1,] 13 16 19 22
[2,] 14 17 20 23
[3,] 15 18 21 24
#當(dāng)k=2時(shí),數(shù)組就是矩陣(matrix)
> data2<-array(1:24,dim=c(3,8))
> data2
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
[1,] 1 4 7 10 13 16 19 22
[2,] 2 5 8 11 14 17 20 23
[3,] 3 6 9 12 15 18 21 24
> is.matrix(data2)
[1] TRUE
2.數(shù)組的訪問
> data<-array(1:24,dim=c(3,4,2))
> data
, , 1
[,1] [,2] [,3] [,4]
[1,] 1 4 7 10
[2,] 2 5 8 11
[3,] 3 6 9 12
, , 2
[,1] [,2] [,3] [,4]
[1,] 13 16 19 22
[2,] 14 17 20 23
[3,] 15 18 21 24
> data[2,3,1]
[1] 8
> data[2,,]
[,1] [,2]
[1,] 2 14
[2,] 5 17
[3,] 8 20
[4,] 11 23
3.數(shù)組的運(yùn)算
數(shù)組的運(yùn)算和矩陣的運(yùn)算基本相同弄诲，這里就不在重復(fù)。
