Importing data into R

Since there are many tutorial written to import and export data, we will refer to pages that do a good job in describing that process (below).

However we have some tips for users:

• Know your working directory

Your working directory is the first place R looks for reading and writing files, so your life will be a lot easier if you know where this directory is. Working directory can be looked up with R via the command:

getwd()

To reassign your working directory, put your directory path in quotes (single or double):

setwd("C:/temp")

or in Linux and Mac

setwd("~/temp")

Once you know your work directory, you can supply a filename of the files residing in the working directory without specifying the exact path, e.g.

read.csv("mydata.csv")

instead of

read.csv("C:/temp/mydata.csv")

• Use a single forward slash for directory path (think Linux/ Mac) or use double backslash in Windows:

setwd("C:\\temp")

• Make sure you use the correctly capitalized file names. This process is easily accomplished with "auto-complete as you type" feature via the "Tab" button across different platforms. Or in Windows, drag-and-drop the file into the R main session window, and the full path of that file will be exposed.

R tutorials on import

1. UCLA R Import Tutorial
2. UCLA R Subsetting Data
3. Quick-R On Importing Data