R is a statistical analyzation language, and that means it is very good at data manipulation and data analyzation. One key way to analyze data is through plotting, and R excels in this field.
An array can be considered as a multiply subscripted collection of data entries, for example, numeric. R allows simple facilities for creating and handling arrays, and in particular the special case of matrices (that is a topic of special section in tutorial II). A dimension vector is a vector of non-negative integers. If its length is k, then the array is k-dimensional, e.g. a matrix is a 2-dimensional array. The dimensions are indexed from one up to the values given in the dimension vector. Arrays can be one-dimensional: such arrays are usually treated in the same way as vectors.
[,1] [,2] [,3]
[1,] 1 2 3
[2,] 4 5 6
[3,] 7 8 9