Collapse According to Groups

This function is generic; method functions can be written to handle specific classes of objects. Currently, only a groupedData method is available.

collapse(object, ...)

Arguments

object

an object to be collapsed, usually a data frame.

...

some methods for the generic may require additional arguments.

Value

will depend on the method function used; see the appropriate documentation.

Author

José Pinheiro and Douglas Bates bates@stat.wisc.edu