有時(shí)，我們想調(diào)換數(shù)組的維度，比如：將data變量的行維度(male, female)變?yōu)榈谌齻€(gè)維度；列維度(young, middle, old)變?yōu)樾芯S度；第三個(gè)維度(A-D)變?yōu)榱芯S度。在R中，可使用aperm()函數(shù)來(lái)實(shí)現(xiàn)這個(gè)功能：

> data

, , A

young middle old

male 1 3 5

female 2 4 6

, , B

young middle old

male 7 9 11

female 8 10 12

, , C

young middle old

male 13 15 17

female 14 16 18

, , D

young middle old

male 19 21 23

female 20 22 24

> new.data <- aperm(data, c(2,3,1)) ##調(diào)換數(shù)組的維度，將data的行維度變?yōu)榈谌齻€(gè)維度；列維度變?yōu)樾芯S度；第三個(gè)維度變?yōu)榱芯S度

> new.data

, , male

A B C D

young 1 7 13 19

middle 3 9 15 21

old 5 11 17 23

, , female

A B C D

young 2 8 14 20

middle 4 10 16 22

old 6 12 18 24