R in a Nutshell, 2nd Edition

Saving and Loading R Objects

R allows you to save and load R data objects to external files.

Saving Objects with save

The simplest way to save an object is with the save function. For example, we could use the following command to save the object top.5.salaries to the file ~/top.5.salaries.RData:

> save(top.5.salaries,file="~/top.5.salaries.RData")

In R, file paths are always specified with forward slashes (“/”), even on Microsoft Windows. So, to save this file to the directory C:\Documents and Settings\me\My Documents\top.5.salaries.rda, you would use the following command:

> save(top.5.salaries,
+   file="C:/Documents and Settings/me/My Documents/top.5.salaries.RData")

Note that the file argument must be explicitly named. (Nine out of 10 times, I forget to do so.) Now you can easily load this object back into R with the load function:

> load("~/top.5.salaries.RData")

Incidentally, files saved in R will work across platforms. (For example, the data files for this book were produced on Mac OS X but work on Windows and Linux.) You can save multiple objects to the same file by simply listing them in the same save command. If you want to save every object in the workspace, you can use the save.image function. (When you quit R, you will be asked if you want to save your current workspace. If you say yes, the workspace will be saved the same way as this function.)

The save function is very flexible and can be used in many different ways. You can save multiple objects, save to files or connections, ...