| update {base} | R Documentation |
Update and Re-fit a Model Call
Description
update will update and (by default) re-fit a model. It does this
by extracting the call stored in the object, updating the call and (by
default) evaluating that call. Sometimes it is useful to call
update with only one argument, for example if the data frame has
been corrected.
Usage
update(object, ...)
update.default(object, formula, ..., evaluate = TRUE)
Arguments
object |
An existing fit from a model function such as |
formula |
Changes to the formula – see |
... |
Additional arguments to the call, or arguments with
changed values. Use |
evaluate |
If true evaluate the new call else return the call. |
Value
If evaluate = TRUE the fitted object, otherwise the updated call.
Author(s)
B.D. Ripley
See Also
update.formula
Examples
oldcon <- options(contrasts = c("contr.treatment", "contr.poly"))
## Annette Dobson (1990) "An Introduction to Generalized Linear Models".
## Page 9: Plant Weight Data.
ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
group <- gl(2, 10, 20, labels = c("Ctl", "Trt"))
weight <- c(ctl, trt)
lm.D9 <- lm(weight ~ group)
lm.D9
summary(lm.D90 <- update(lm.D9, . ~ . - 1))
options(contrasts = c("contr.helmert", "contr.poly"))
update(lm.D9)
options(oldcon)