crosstab {ecodist} | R Documentation |
Converts field data of the form site, species, observation into a matrix.
crosstab(rowlab, collab, values, type = "sum")
rowlab |
row labels, e.g. site names. |
collab |
column labels, e.g. species names. |
values |
data values. |
type |
function to use to combine data, one of "sum" (default), "min", "max", "mean". |
Field data are often recorded as a separate row for each site-species combination. This function turns them into a matrix for further analysis based on unique row and column labels.
The three vectors should all be the same length (including duplicates).
matrix with rowlab as row headings, collab as columns, and values as the data.
Sarah Goslee, Sarah.Goslee@ars.usda.gov
# Make a random example plotnames <- sort(rep(1:5, 3)) speciesnames <- rep(c("A", "B", "C"), 5) freqdata <- runif(15) data.m <- crosstab(plotnames, speciesnames, freqdata)