2) Issue commands to the R Console.

This Blog entry is from the Getting Started in R section in Learn R.

R is an interpreted language for mathematical and statistical computing. R processes as script, line by line.  In this example the sum of 1 + 1 will be returned, which will of course be 2.  To perform such a calculation type:

type-1-plus-1-in-r-console.png

Press the Enter key to commit and execute the line of script:

result-of-1-plus-1-in-r-console.png

It can be seen that a line has been returned showing [1] 2, where [1] is the position in the result vector, where 2 is the actual value returned from the line of script.  The mathematical operators (in this case +) are much the same as Excel:

·         + Addition.

·         - Subtract

·         / Divide

·         * Multiply

This Blog entry has shown a simple line of script being written, executed and returned by R.  Although rudimentary, it is an R program.

To exit the R console, hold down the CTRL key and the D key:

saving-r-workspace-on-exit.png

There are three options presented when exiting the R console:

·         y: Save the workspace image for reloading.  This will keep everything in the current session.

·         n: Clear the workspace so that the next time r is loaded it will be afresh.

·         c: Cancel and go back to the workspace.

In this example, type:

y
typing-y-to-save-the-r-workspace-on-exit.png

Press the Enter key to commit the command:

r-has-exited-after-saving-the-workspace.png

Notice that an error was returned ‘Unable to open .Rhistory’.  The error is created as the operating system will not allow the user to write to the same directory as R is running, which introduces the concept of working directories, as follows.