Reshaping Data with the reshape Package

Abstract

This paper presents the reshape package for R, which provides a common framework for many types of data reshaping and aggregation. It uses a paradigm of `melting' and `casting', where the data are `melted' into a form which distinguishes measured and identifying variables, and then `cast' into a new shape, whether it be a data frame, list, or high dimensional array. The paper includes an introduction to the conceptual framework, practical advice for melting and casting, and a case study.