R and MATLAB

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

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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.

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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

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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.

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