prune.rpart              package:rpart              R Documentation

Cost-complexity Pruning of an Rpart Object

Description:

     Determines a nested sequence of subtrees of the supplied 'rpart'
     object  by recursively 'snipping' off the least important splits,
     based on the  complexity parameter ('cp').

Usage:

     prune(tree, ...)

     ## S3 method for class 'rpart':
     prune(tree, cp, ...)

Arguments:

    tree: fitted model object of class 'rpart'.  This is assumed to be
          the result  of some function that produces an object with the
          same named  components as that returned by the 'rpart'
          function.  

      cp: Complexity parameter to which the 'rpart' object will be
          trimmed. 

     ...: further arguments passed to or from other methods.

Value:

     A new 'rpart' object that is trimmed to the value 'cp'.

See Also:

     'rpart'

Examples:

     data(car.test.frame)
     z.auto <- rpart(Mileage ~ Weight, car.test.frame)
     zp <- prune(z.auto, cp=0.1)
     plot(zp) #plot smaller rpart object

