Snip Subtrees of an Arbor Object

DESCRIPTION:

Creates a snipped arbor object, containing the nodes that remain after selected subtrees have been snipped off. The user can snip nodes using the toss arguement, or interactively by clicking the mouse button on specified nodes within the graphics window.

USAGE:

snip.arbor(x, toss) 

REQUIRED ARGUMENTS:

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

OPTIONAL ARGUMENTS:

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.

VALUE:

an arbor object containing the nodes that remain after specified or selected subtrees have been snipped off.

DETAILS:

A dendrogram of tree 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 yvalue, 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 arbor object. See the documentation for the specific graphics device for details on graphical input techniques.

SEE ALSO:

EXAMPLES:

z.survey <- arbor(market.survey)  # grow the arbor object 
plot(z.survey)  # plot the tree 
text(z.survey)  # add text to tree
z.survey2 <- snip.arbor(z.survey,toss=2)  # trim subtree at node 2 
plot(z.survey2)  # plot new tree 
text(z.survey2)  # add text to tree
# can also interactively select the node using the mouse in the 
# graphics window