These presentations describe how to manipulate and subset R data objects using indexing. The slides for this material can be found here.

**Indexing Vectors to Manipulate Data in R**

How to index vectors by position, logical expression and name. Using conditional expressions and logical indexes to identify and select one vector against another. Using logical indexing to categorize a variable into mutually exclusive groups.

**Indexing Matrices and Arrays in R**

How to index matrices and arrays by position, name and logical expression.

**Indexing Lists in R**

How to index lists by position using the double bracket notation, by logical expression, and by name. Using indexing to extract results from functions that return lists.

**Indexing and Manipulating Data Frames in R**

How to index data frame observations (rows) and variables (columns) by position, name and logical expressions to manipulate and recode or replace data elements.

**Subsetting Data Frames in R**

Subsetting a data frame using indexing and logical expressions to restrict rows and variables. Introduction to the base R function subset() as an alternative to indexing.