机器学习中具有10倍交叉验证的代码

Question

我刚开始学习机器。我试着用C5.0模型进行10倍的交叉验证。我要求代码返回kappa值。

folds = createFolds(mdd.cohort1$edmsemmancomprej, k=10)
str(folds)
mdd.cohort1_train = mdd.cohort1[-folds$Fold01,]
mdd.cohort1_test = mdd.cohort1[folds$Fold01,]
library(caret)
library(C5.0)
library(irr)
set.seed(123)
folds = createFolds(mdd.cohort1$edmsemmancomprej, k=10)

cv_results = lapply(folds, function(x) 
{mdd.cohort1_train = mdd.cohort1[-x, ] 
mdd.cohort1_test = mdd.cohort1[x, ] 
mdd.cohort1_model = C5.0(edmsemmancomprej ~., data = mdd.cohort1_train) 
mdd.cohort1_pred = predict(mdd.cohort1_model, mdd.cohort1_test) 
mdd.cohort1_actual = mdd.cohort1_test$edmsemmancomprej 
kappa = kappa2(data.frame(mdd.cohort1_actual, mdd.cohort1_pred))$value    return(kappa)})

给出以下错误修正：

Error: unexpected symbol in:
"mdd.cohort1_actual = mdd.cohort1_test$edmsemmancomprej
kappa = kappa2(data.frame(mdd.cohort1_actual, mdd.cohort1_pred))$value return"

有人知道发生了什么吗？提前谢谢你！

Answer 1

如果没有一个可重复的例子，这是有点困难的，但我认为分享最后一行的回报才是原因。为了提高可读性，我重新格式化了您的代码。

library(caret)
library(C5.0)
library(irr)   

folds = createFolds(mdd.cohort1$edmsemmancomprej, k=10)

str(folds)

mdd.cohort1_train = mdd.cohort1[-folds$Fold01,]
mdd.cohort1_test = mdd.cohort1[folds$Fold01,]

set.seed(123)
folds = createFolds(mdd.cohort1$edmsemmancomprej, k=10)

cv_results = lapply(folds, function(x) {
  mdd.cohort1_train = mdd.cohort1[-x, ] 
  mdd.cohort1_test = mdd.cohort1[x, ] 
  mdd.cohort1_model = C5.0(edmsemmancomprej ~., data = mdd.cohort1_train) 
  mdd.cohort1_pred = predict(mdd.cohort1_model, mdd.cohort1_test) 
  mdd.cohort1_actual = mdd.cohort1_test$edmsemmancomprej 
  kappa = kappa2(data.frame(mdd.cohort1_actual, mdd.cohort1_pred))$value    
  return(kappa)
  })