| snip.rpart {rpart} | R Documentation |
Snip Subtrees of an Rpart Object
Description
Creates a "snipped" rpart object, containing the nodes that remain after selected subtrees have been snipped off. The user can snip nodes using the toss argument, or interactively by clicking the mouse button on specified nodes within the graphics window.
Usage
snip.rpart(x, toss)
Arguments
x |
fitted model object of class |
toss |
an integer vector containing indices (node numbers) of all subtrees to be snipped off. If missing, user selects branches to snip off as described below. |
Details
A dendrogram of rpart is expected to be visible on the graphics
device, and a graphics input device (e.g., a mouse) is required. Clicking
(the selection button) on a node displays the node number, sample
size, response y-value, and Error (dev). Clicking a second time on the
same node snips that subtree off and visually erases the subtree.
This process may be repeated an number of times. Warnings result from
selecting the root or leaf nodes. Clicking the exit button will stop
the snipping process and return the resulting rpart object.
See the documentation for the specific graphics device for details on graphical input techniques.
Value
A rpart object containing the nodes that remain after specified or
selected subtrees have been snipped off.
Warning
Visually erasing the plot is done by over-plotting with the background colour. This will do nothing if the background is transparent (often true for screen devices).
See Also
Examples
## dataset not in R
## Not run:
z.survey <- rpart(market.survey) # grow the rpart object
plot(z.survey) # plot the tree
z.survey2 <- snip.rpart(z.survey, toss = 2) # trim subtree at node 2
plot(z.survey2) # plot new tree
# can also interactively select the node using the mouse in the
# graphics window
## End(Not run)