gapply {nlme} | R Documentation |
Applies the function to the distinct sets of rows of the data frame
defined by groups
.
gapply(object, which, FUN, form, level, groups, ...)
object |
an object to which the function will be applied - usually
a groupedData object or a data.frame . Must inherit from
class data.frame .
|
which |
an optional character or positive integer vector
specifying which columns of object should be used with
FUN . Defaults to all columns in object .
|
FUN |
function to apply to the distinct sets of rows
of the data frame object defined by the values of
groups .
|
form |
an optional one-sided formula that defines the groups.
When this formula is given the right-hand side is evaluated in
object , converted to a factor if necessary, and the unique
levels are used to define the groups. Defaults to
formula(object) .
|
level |
an optional positive integer giving the level of grouping to be used in an object with multiple nested grouping levels. Defaults to the highest or innermost level of grouping. |
groups |
an optional factor that will be used to split the
rows into groups. Defaults to getGroups(object, form, level) .
|
... |
optional additional arguments to the summary function
FUN . Often it is helpful to specify na.rm = TRUE .
|
Returns a data frame with as many rows as there are levels in the
groups
argument.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
## Find number of non-missing "conc" observations for each Subject gapply( Phenobarb, FUN = function(x) sum(!is.na(x$conc)) )