*This Blog entry is from the Data Structures section in **Learn R**.*

It is helpful for reference to label a Vector. It is possible also to label the rows and the columns of a matrix in a similar fashion using the rownames() and colnames() function.

To set column names assign a Vector to the colnames() function, where the colnames() function accepts the matrix as its argument:

`colnames(OverspillMatrix) <- c("Example1","Example2","Example3","Example4")`

Run the line of script to console:

The rownames() function has a similar signature and takes a Vector of row names:

`rownames(OverspillMatrix) <- c("Row1","Row2","Row3")`

Run the line of script to console:

The matrix is now labelled in both directions and can be inspected by typing:

`OverspillMatrix`

Run the line of script to console: