Studies in contemporary community ecology make use of data from a wide variety of sources, including information on dispersal barriers, functional traits, species interactions, and spatiotemporal and phylogenetic autocorrelation. The recognition of the importance of these factors has led to complex multiple-table data structures. For a simple example, when both environmental variables and functional traits are used to help understand variation in community composition, one obtains a multiple-table data set that cannot easily be organized into a standard data table with rows and columns representing replicates and variables. Nevertheless, most statistical tools require such a single-table data format. Storing multiple-table data in a single table often results in either large numbers of meaningless missing values or storage of redundant information. Even in the more flexible R computing environment, storing complex data in multiple tables (i.e. data frames in R-speak) often results in long difficult-to-read workflows. My frustration with these issues led me to develop the multitable package (on CRAN). This package introduces a new data object called a data.list, which organizes several data tables as a single R object. The primary goal of multitable is to provide a more intuitive framework for manipulating multiple-table data in R. As data.lists can be coerced to data.frames, they can be used with all R functions that accept an object that is coercible to a data.frame (e.g. lm; plot; lme; and many more). In essence, data.list objects work much like familiar data.frame objects, but handle a richer variety of data structures.
Here are the package websites: http://multitable.r-forge.r-project.org/ http://cran.r-project.org/web/packages/multitable/index.html A quick introduction to multitable is here: http://cran.r-project.org/web/packages/multitable/vignettes/multitable.pdf I am very interested in constructive feedback, as I plan to continue to develop multitable to meet new challenges that arise in multiple-table data analysis -- particularly in ecology. Steve Walker -- ---------------------------------------------------- Steven C Walker Postdoctoral researcher Département de Sciences Biologiques Université de Montréal https://sites.google.com/site/stevencarlislewalker/ ----------------------------------------------------
