Select the last n columns of data frame in R

Question

Is there a way to systematically select the last columns of a data frame? I would like to be able to move the last columns to be the first columns, but maintain the order of

Answer 1

The problem described doesn't match the title, and existing answers address the moving columns part, doesn't really explain how to select last N columns.

If you wanted to just select the last n columns in a matrix/data frame without knowing the column names:

mydata2[,ncol(mydata2)]

and if you want last n columns, try

mydata[,(ncol(mydata2)-n-1):ncol(mydata2)]

A little cumbersome, but works. Could write wrapper function if you plan to use it regularly.