rpart
Recursive Partitioning and Regression Trees
Description
Fit a rpart
model
Usage
rpart(formula, data, weights, subset, na.action = na.rpart, method, model = FALSE, x = FALSE, y = TRUE, parms, control, cost, ...)
Arguments
formula | a formula, with a response but no interaction terms. If this a a data frame, that is taken as the model frame (see |
data | an optional data frame in which to interpret the variables named in the formula. |
weights | optional case weights. |
subset | optional expression saying that only a subset of the rows of the data should be used in the fit. |
na.action | the default action deletes all observations for which |
method | one of Alternatively, |
model | if logical: keep a copy of the model frame in the result? If the input value for |
x | keep a copy of the |
y | keep a copy of the dependent variable in the result. If missing and |
parms | optional parameters for the splitting function. |
control | a list of options that control details of the |
cost | a vector of non-negative costs, one for each variable in the model. Defaults to one for all variables. These are scalings to be applied when considering splits, so the improvement on splitting on a variable is divided by its cost in deciding which split to choose. |
... | arguments to |
Details
This differs from the tree
function in S mainly in its handling of surrogate variables. In most details it follows Breiman et. al (1984) quite closely. R package tree provides a re-implementation of tree
.
Value
An object of class rpart
. See rpart.object
.
References
Breiman L., Friedman J. H., Olshen R. A., and Stone, C. J. (1984) Classification and Regression Trees. Wadsworth.
See Also
rpart.control
, rpart.object
, summary.rpart
, print.rpart
Examples
fit <- rpart(Kyphosis ~ Age + Number + Start, data = kyphosis) fit2 <- rpart(Kyphosis ~ Age + Number + Start, data = kyphosis, parms = list(prior = c(.65,.35), split = "information")) fit3 <- rpart(Kyphosis ~ Age + Number + Start, data = kyphosis, control = rpart.control(cp = 0.05)) par(mfrow = c(1,2), xpd = NA) # otherwise on some devices the text is clipped plot(fit) text(fit, use.n = TRUE) plot(fit2) text(fit2, use.n = TRUE)
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Licensed under the GNU General Public License.