# Data Input

Unlike **SAS**, which has DATA and PROC steps, **R** has data structures (vectors, matrices, arrays,
data frames) that you can operate on through functions that perform statistical analyses and create graphs. In this way,
**R** is similar to PROC IML.

This section describes how to enter or import data into **R**, and how to prepare it for use in statistical analyses.
Topics include **R** data structures, importing data
(from Excel, SPSS, SAS, Stata, and ASCII Text Files), entering data from the keyboard, creating an
interface with a database management system, exporting data
(to Excel, SPSS, SAS, Stata, and Tab Delimited Text Files), annotating data (with variable
labels and value labels), and listing data. In addition,
methods for handling missing values and date values are presented.