object has a single grouping factor, it is returned
unchanged. Else, it is summarized by the values of the
displayLevel
grouping factor (or the combination of its values
and the values of the covariate indicated in
preserve, if any is
present). The collapsed data is used to produce a new
groupedData
object, with grouping factor given by the
displayLevel
factor.
collapse(object, collapseLevel, displayLevel, outer, inner, preserve,
FUN, subset)
groupedData,
generally with multiple grouping factors.
collapseLevel.
displayLevel
grouping factor. If equal to
TRUE, the
displayLevel
element
attr(object, "outer") is used to indicate the
outer covariates. An outer covariate is invariant within the sets
of rows defined by the grouping factor. Ordering of the groups is
done in such a way as to preserve adjacency of groups with the same
value of the outer variables. Defaults to
NULL, meaning that
no outer covariates are to be used.
displayLevel grouping
factor. If equal to
TRUE,
attr(object, "outer") is used
to indicate the inner covariate. An inner covariate can change within
the sets of rows defined by the grouping factor. Defaults to
NULL, meaning that no inner covariate is present.
collapseLevel grouping factor. The collapsing factor is
obtained by pasting together the levels of the
collapseLevel
grouping factor and the values of the covariate to be
preserved. Default is
NULL, meaning that no covariates need to
be preserved.
object that vary within the
groups defined by
collapseLevel. Invariant variables are
always summarized by group using the unique value that they assume
within that group. If
FUN is a single
function it will be applied to each non-invariant variable by group
to produce the summary for that variable. If
FUN is a list of
functions, the names in the list should designate classes of
variables in the data such as
ordered,
factor, or
numeric. The indicated function will be applied to any
non-invariant variables of that class. The default functions to be
used are
mean for numeric factors, and
Mode for both
factor and
ordered. The
Mode function, defined
internally in
gsummary, returns the modal or most popular
value of the variable. It is different from the
mode function
that returns the S-language mode of the variable.
NULL, meaning that all levels are
used.
groupedData object with a single grouping factor given by the
displayLevel
grouping factor, resulting from collapsing
object
over the levels of the
collapseLevel grouping
factor.
Pinheiro, J.C. and Bates, D.M. (1997) "Future Directions in Mixed-Effects Software: Design of NLME 3.0" available at http://nlme.stat.wisc.edu
# collapsing by Dog collapse(Pixel, collapse = 1) # same as collapse(Pixel, collapse = "Dog")