20.19 Complexity Parameter
We can print a table of optimal prunings based on a complexity
parameter using rpart::printcp(). The data is actually stored as
model$cptable
.
printcp(model)
##
## Classification tree:
## rpart(formula = form, data = ds[tr, vars], model = TRUE)
##
## Variables actually used in tree construction:
## [1] humidity_3pm wind_gust_speed
##
## Root node error: 26002/123722 = 0.21016
##
## n= 123722
##
## CP nsplit rel error xerror xstd
## 1 0.145258 0 1.00000 1.00000 0.0055114
## 2 0.034978 1 0.85474 0.85432 0.0051920
## 3 0.010000 3 0.78479 0.78905 0.0050313
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