R Projects and Files in a Project

Paths and Directories

Paths and directories are a little complicated because there are two basic styles of paths: Mac/Linux and Windows. There are three chief ways in which they differ:

1. The most important difference is how you separate the components of the path. Mac and Linux uses slashes (e.g. plots/diamonds.pdf) and Windows uses backslashes (e.g. plots\diamonds.pdf). R can work with either type (no matter what platform you're currently using), but unfortunately, backslashes mean something special to R, and to get a single backslash in the path, you need to type two backslashes! That makes life frustrating, so I recommend always using the Linux/Mac style with forward slashes.

2. Absolute paths (i.e. paths that point to the same place regardless of your working directory) look different. In Windows they start with a drive letter (e.g. C:) or two backslashes (e.g. \\servername) and in Mac/Linux they start with a slash "/" (e.g. /users/hadley). You should never use absolute paths in your scripts, because they hinder sharing: no one else will have exactly the same directory configuration as you.

3. The last minor difference is the place that ~ points to. ~ is a convenient shortcut to your home directory. Windows doesn't really have the notion of a home directory, so it instead points to your documents directory.