R Language – Arrays (Array)

1. Array array() Function

myarray <- array(vector, dimensions, dimnames) #vector: data to store #dimensions: numeric vector #dimnames: list #The data pattern of the array is unique #An array is a three-dimensional data structure

2. Creating an Array

vector1 <- c(1,2,3) vector2 <- c(4,5,6,7,8) vector3 <- c(vector1,vector2) vector3[1] 1 2 3 4 5 6 7 8 class(vector3)[1] "numeric" myarray <- array(vector3, dim = c(3,3,2))   #Create 2 matrices of 3*3 myarray, , 1
     [,1] [,2] [,3][1,]    1    4    7[2,]    2    5    8[3,]    3    6    1
, , 2
     [,1] [,2] [,3][1,]    2    5    8[2,]    3    6    1[3,]    4    7    2
#Naming rows, columns, and matrices row.names <- c("Row1","Row2","Row3") column.names <- c("Col1","Col2","Col3") matrix.names <- c("Matrix1","Matrix2") myarray <- array(c(vector1,vector2),dim=c(3,3,2),+       dimnames = list(row.names,column.names,matrix.names)) myarray, , Matrix1
     Col1 Col2 Col3Row1    1    4    7Row2    2    5    8Row3    3    6    1
, , Matrix2
     Col1 Col2 Col3Row1    2    5    8Row2    3    6    1Row3    4    7    2

3. Accessing Array Elements

myarray[1,,]     Matrix1 Matrix2Col1       1       2Col2       4       5Col3       7       8 myarray[,1,]     Matrix1 Matrix2Row1       1       2Row2       2       3Row3       3       4 myarray[,,1]     Col1 Col2 Col3Row1    1    4    7Row2    2    5    8Row3    3    6    1 myarray[1,1,1][1] 1 myarray[1,2,2][1] 5