R - tree lib

Fit a Classification or Regression Tree 

拟合分类和回归tree

>install.packages(tree)
>help(tree)
主方法 :

tree(formula = formula(data), data = parent.frame(),
     weights, subset,
     na.action = na.pass, control = tree.control(nobs, ...),
     method = "recursive.partition",
     split = c("deviance", "gini"),
     model = NULL, x = FALSE, y = TRUE, wts = TRUE, ...)

> data(cpus, package="MASS")
1> cpus.ltr <- tree(log10(perf) ~ syct + mmin + mmax + cach + chmin + chmax, data=cpus)
# 1 与 2 相同
2> attach(cpus)
2> cpus.ltr <- tree(log10(perf) ~ syct + mmin + mmax + cach + chmin + chmax)
#这能说明 参数中 formula = formula(data), data = parent.frame()

library(MASS)
data(cpus)
cpus.ltr <- tree(log10(perf) ~ syct+mmin+mmax+cach+chmin+chmax, cpus)
cpus.ltr
summary(cpus.ltr)
plot(cpus.ltr);  text(cpus.ltr)

data(iris)
ir.tr <- tree(Species ~., iris)
ir.tr
summary(ir.tr)