Array is a data object which allows users to store data in more than two dimensions. array() function is used to create an array in R.
How to create an array
Syntax
arrayName <- array(data, dim= (rowSize, columnSize, matrices, dimNames))
- data : data is an input vector
- rowSize : defines no of row elements array can store
- columnSize : defines no of column elements array can store
- dimNames : specifies row and column names
- matrices : array can consists of multi-dimensional matrices
Example
x <- c(1,2,3)
y <- c(4,5,6,7,8,9)
arr <- array(c(x,y),dim=c(3,3,2)) # 3 rows, 3 columns and 2 matrices
print(arr)
Check Result here
Below is an example which shows you how to name rows, columns and matrices.
x <- c(1,2,3)
y <- c(4,5,6,7,8,9)
row.names <- c("row-1","row-2","row-3")
col.names <- c("col-1","col-2","col-3")
matrix.names <- c("Matrix-1","Matrix-2","matrix-3")
arr <- array(c(x,y),dim=c(3,3,3), dimnames = list(row.names, col.names, matrix.names)) # 3 rows, 3 columns and 3 matrices
print(arr)
Check Result here
How to access Array elements
Array elements are accessed by using it's indices.
x <- c(1,2,3)
y <- c(4,5,6,7,8,9)
row.names <- c("row-1","row-2","row-3")
col.names <- c("col-1","col-2","col-3")
matrix.names <- c("Matrix-1","Matrix-2","matrix-3")
arr <- array(c(x,y),dim=c(3,3,3), dimnames = list(row.names, col.names, matrix.names)) # 3 rows, 3 columns and 3 matrices
print(arr)
print(arr[,,3]) # prints 3rd matrix
print(arr[2,,2]) # prints 2nd row in second matrix
print(arr[3,3,1]) # prints 3rd row 3rd column element of 1st matrix