r语言 - 尝试构建树给出：'[.default'(xj， i) 中的错误：下标类型"列表"无效

Question

运行以下代码：

library(tree)
library(ISLR)
library(dplyr)
Carseats <- Carseats %>% mutate(High = factor(ifelse(Sales <= 8, "No", "Yes")))
set.seed(2)
train_sample <- sample(nrow(Carseats), 200)
carseats_train <- Carseats[train_sample,]
carseats_test <- Carseats[-train_sample,]
tree.carseats <- tree(High~ . -Sales, Carseats, subset = carseats_train)

这将输出错误：

Error in `[.default`(xj, i) : invalid subscript type 'list'

造成这种情况的原因是什么？我该如何处理？

Answer 1

我想错了。我对树的输入不正确。即CCD_ 1参数。这需要是一个指定要使用的子集的表达式。

可以使用train_sample作为输入来固定代码。

library(tree)
library(ISLR)
library(dplyr)
Carseats <- Carseats %>% mutate(High = factor(ifelse(Sales <= 8, "No", "Yes")))
set.seed(2)
train_sample <- sample(nrow(Carseats), 200)
carseats_test <- Carseats[-train_sample,]
tree.carseats <- tree(High~ . -Sales, Carseats, subset = train_sample)