Class counts
Syntax
P = classcount(t)
P = classcount(t,nodes)
Description
P = classcount(t) returns an n-by-m array P of
class counts for the nodes in the classification tree t,
where n is the number of nodes and m is
the number of classes. For any node number i, the
class counts P(i,:) are counts of observations
(from the data used in fitting the tree) from each class satisfying
the conditions for node i.
P = classcount(t,nodes) takes a vector nodes of
node numbers and returns the class counts for the specified nodes.
Examples
Create a classification tree for Fisher's iris data:
load fisheriris;
t = classregtree(meas,species,...
'names',{'SL' 'SW' 'PL' 'PW'})
t =
Decision tree for classification
1 if PL<2.45 then node 2 elseif PL>=2.45 then node 3 else setosa
2 class = setosa
3 if PW<1.75 then node 4 elseif PW>=1.75 then node 5 else versicolor
4 if PL<4.95 then node 6 elseif PL>=4.95 then node 7 else versicolor
5 class = virginica
6 if PW<1.65 then node 8 elseif PW>=1.65 then node 9 else versicolor
7 class = virginica
8 class = versicolor
9 class = virginica
view(t)
P = classcount(t)
P =
50 50 50
50 0 0
0 50 50
0 49 5
0 1 45
0 47 1
0 2 4
0 47 0
0 0 1References
[1] Breiman, L., J. Friedman, R. Olshen, and
C. Stone. Classification and Regression Trees.
Boca Raton, FL: CRC Press, 1984.
See Also
classregtree | numnodes
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