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: 32740/151934=0.21549
##
## n= 151934
##
## CP nsplit rel error xerror xstd
## 1 0.157575 0 1.00000 1.00000 0.0048951
## 2 0.033903 1 0.84243 0.84633 0.0045974
## 3 0.010000 3 0.77462 0.77850 0.0044485
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