nlme (version 3.1-31)

gapply: Apply a Function by Groups

Description

Applies the function to the distinct sets of rows of the data frame defined by groups.

Usage

gapply(object, which, FUN, form, level, groups, ...)

Value

Returns a data frame with as many rows as there are levels in the groups argument.

See Also

gsummary

Examples

data( Phenobarb )
## Find number of non-missing "conc" observations for each Subject
gapply( Phenobarb, FUN = function(x) sum(!is.na(x$conc)) )