7
Running Code from Files: Scripts
If you w ill be entering more than a small handful of commands, rather than simply typing
them at the command prompt, it is prudent to use an editor to place them in a file. This
allows you to fix any errors in your code without needing to retype all of your commands.
It is also ver y useful if you are experimenting with some properties of a figure to get it just
right; when you have it just the way you like, you can save your commands to a file so that
you can easily reproduce or modify the figure again later.
Both R and MATLAB have built-in editors
1
and ways to execute commands from their
built-in editors and from files. Following standard computer ter minology, a file (or editor
window) containing some R or MATLAB commands is typically called a script.
7.1 Current working directory
Both R and MATLAB use what is called a current working directory.
2
The current working
directory is the default location for reading and writing files.
R
The command getwd() will display the current working directory. In the OS-X ver-
sion of R, it is a lso displayed at the top of the Conso le window. You can use
setwd('some/path/here') to set the current working directory to the specified path.
Use fo rward slashes as the path separators. Tilde expansion will be done on sys-
tems that support it, where a tilde represents your home directory. (You can enter
path.expand('~') to see what R considers your home directory to be.) So for ex-
ample, on most platforms you can enter a command like setwd('~/R-documents'),
and under an appropriate version of Windows you could enter a command like
setwd('C:/Users/hiebeler/Documents/R-documents').
You can see a listing of the files in the current working directory via the command dir(),
and can make a new directory (folder) named foo via dir.create('foo').
MATLAB
The command p wd s hows (prints) the current working directory, or you can also use cd
with no arguments. Yo u can use cd with an argument to set the working directory, e.g., cd
some/path/here. Tilde expansion will be done on s ome operating systems. Note that if your
path contains directories with spaces in them, you’ll ne ed to use the function-call form of
1
The standard Linux version of R does not have a GUI with an editor, but there are facil ities to integrate
the Emacs editor with R. Also see the free and open source RStudio project.
2
“Directory” is the traditional Unix name for what many people refer to as a “f older” under Windows
and Mac OS-X.
77

Get R and MATLAB now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.