This Blog entry is from the Data Structures section in Learn R.
As a matrix is made up of vectors, it is logical to expect it to bear some resemblance in the way selection from a matrix takes place. All subscripting in a separate dimension when specified inside the [] square brackets, as separate arguments. The first argument inside the square brackets relates to the row, the next the column.
To obtain the value in a given position of a matrix, in this case two down, three across, type:
OverspillMatrix[2,3]

Run the line of script to console:

It can be seen that the value 2 has been returned which corresponds to the position specified:
