| stack {base} | R Documentation |
Stacking vectors concatenates multiple vectors into a single vector along with a factor indicating where each observation originated. Unstacking reverses this operation.
stack(x, ...) ## Default S3 method: stack(x, ...) ## S3 method for class 'data.frame': stack(x, select, ...) unstack(x, ...) ## Default S3 method: unstack(x, form, ...) ## S3 method for class 'data.frame': unstack(x, form = formula(x), ...)
x |
object to be stacked or unstacked |
select |
expression, indicating variables to select from a data frame |
form |
a two-sided formula whose left side evaluates to the
vector to be unstacked and whose right side evaluates to the
indicator of the groups to create. Defaults to formula(x)
in unstack.data.frame. |
... |
further arguments passed to or from other methods. |
The stack function is used to transform data available as
separate columns in a data frame or list into a single column that can
be used in an analysis of variance model or other linear model. The
unstack function reverses this operation.
unstack produces a list of columns according to the formula
form. If all the columns have the same length, the resulting
list is coerced to a data frame.
stack produces a data frame with two columns
values |
the result of concatenating the selected vectors in
x |
ind |
a factor indicating from which vector in x the
observation originated |
Douglas Bates
require(stats) formula(PlantGrowth) # check the default formula pg <- unstack(PlantGrowth) # unstack according to this formula pg stack(pg) # now put it back together stack(pg, select = -ctrl) # omitting one vector