从文本变量读取rpart输入参数 [英] Reading rpart Input Parameters from a Text Variable

问题描述

我正在使用rpart来制作决策树.例如:

I'm using rpart to make a decision tree. For example:

fit <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)

如何从文本文件中读取公式部分，并以rpart喜欢的格式获取它?我尝试过:

How do I read in the formula part from a text file and get it in a format that rpart likes? I've tried:

predictor_variables <- c("Age", "Number", "Start")
rpart_formula <- Kyphosis ~ parse(text=paste(predictor_variables, collapse="+"))
fit <- rpart(rpart_formula, data=kyphosis)

但是我得到一个错误:

 invalid type (expression) for variable 'parse(text = paste(predictor_variables, collapse = "+"))'

如何格式化rpart_formula，以便rpart正确看到它?

How can I format rpart_formula so that rpart sees it correctly?

推荐答案

使用as.formula:

rpart_formula <- as.formula(
    paste("Kyphosis ~ ", 
          paste(predictor_variables, collapse = " + "), 
          sep = ""
    )
)

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