update.xtabs {vcdExtra}

Update method for a xtabs object

Description

Provides an update method for "xtabs" objects, typically by removing terms from the formula to collapse over them.

Usage

## S3 method for class 'xtabs'
update(object, formula., ..., evaluate = TRUE)

Arguments

object

An existing "xtabs" object

formula.

Changes to the formula ? see update.formula for details

...

Additional arguments to the call, or arguments with changed values.

evaluate

If TRUE, evaluate the new call else return the call

Value

If evaluate == TRUE, the new "xtabs" object, otherwise the updated call

Author(s)

Michael Friendly

See Also

update.formula for details on updates to model formulae

margin.table does something similar, collapse.table collapses category levels

Examples

vietnam.tab <- xtabs(Freq ~ sex + year + response, data=Vietnam)

update(vietnam.tab, formula = ~ . -year)