The Art of R Programming

Reading and Writing Files

Now that we’ve covered the basics of I/O, let’s get to some more practical applications of reading and writing files. The following sections discuss reading data frames or matrices from files, working with text files, accessing files on remote machines, and getting file and directory information.

Reading a Data Frame or Matrix from a File

In Section 5.1.2, we discussed the use of the function read.table() to read in a data frame. As a quick review, suppose the file z looks like this:

name age
John 25
Mary 28
Jim 19

The first line contains an optional header, specifying column names. We could read the file this way:

> z <- read.table("z",header=TRUE)
> z
  name age
1 John  25
2 Mary  28
3  Jim  19

Note that scan() would not work ...