表中实际值和预测值的长度有何不同？出现错误 - 所有参数必须具有相同的长度答案

【问题标题】：How is the length of actual and predicted value different in table? Getting error- all arguments must have the same length表中实际值和预测值的长度有何不同？出现错误 - 所有参数必须具有相同的长度
【发布时间】：2021-08-25 03:02:07
【问题描述】：

这是我的逻辑回归代码：

data_raw = data.frame(
    Var1= c(11, 5, 1, 0, 5, 1, 0, 0, 1, 0),
  Var2= c(11, 5, 0, 0, 2, 1, 0, 2, 0, 2),
  Var3= c(10, 7, 15, 9, 16, 9, 13, 15, 11, 17),
  Var4= c(6, 10, 36, 10, 9, 12, 17, 5, 12, 14),
  Var5= c(7, 26, 24, 16, 23, 25, 15, 10, 15, 22),
  Var6= c(0, 0, 1, 0, 0, 2, 1, 0, 0, 0),
  Var7= c(17, 21, 23, 16, 26, 22, 11, 9, 9, 9),
  Var8= c(1, 0, 1, 0, 3, 5, 2, 0, 0, 0),
  Var9= c(3, 0, 3, 3, 2, 0, 1, 3, 3, 2),
  Var10= c(3, 0, 3, 3, 2, 0, 1, 3, 3, 2),
  Var11= c(7, 2, 6, 7, 7, 5, 3, 5, 5, 4),
  Var12= c(4, 3, 3, 4, 2, 3, 4, 8, 7, 5),
  Var13= c("Summer", "Summer", "Summer", "Summer", "Autumn", "Autumn", "Summer", "Summer", "Summer", "Summer"),
  Var14= c("Both host", "Both host", "Both host", "Host Visitor", "Both host", "Both host", "Both host", "Both host", "Both host", "Both host"),
  Var15= c("Home", "Similar", "Similar", "Similar", "Similar", "Similar", "Home", "Home", "Home", "Similar"),
  Winner = c("Win", "Loss", "Win", "Loss", "Win", "Win", "Loss", "Loss", "Win", "Loss"),
  stringsAsFactors = TRUE
)
set.seed(123) # <-- edit
data_shuffled = sample(1:nrow(data_raw))

data_new = data_raw[data_shuffled, ]

create_train_test <- function(data_new, size = 0.8, train = TRUE) {
  n_row = nrow(data_new)
  total_row = size * n_row
  train_sample = 1: total_row
  if (train == TRUE) {
    return (data_new[train_sample, ])
  } else {
    return (data_new[-train_sample, ])
  }
}

data_train <- create_train_test(data_new, size= 0.8, train = TRUE)
data_test <- create_train_test(data_new, size= 0.8, train = FALSE)

mymodel = glm(Winner~., data= data_train, family= binomial)

res2 = predict(mymodel, data= data_test, type="response")
pred2= ifelse(res2>0.5, 1, 0)
tab2= table(data_test$Winner, pred2)

在最终代码中，我收到一个错误，即所有参数都应具有相同的长度。经过检查，我发现它们确实有不同的长度。为什么会发生 BTW？我使用了不同的数据集，它工作正常。编辑。我已经包含了一个示例数据集。

【问题讨论】：

您的数据是否存在缺失值？如果您包含一个简单的reproducible example 和可用于测试和验证可能解决方案的示例输入，则更容易为您提供帮助。我们无法真正将str() 复制/粘贴到 R 中进行测试。
@MrFlick 我已经包含了一个示例数据。原始数据集中没有 NA 值。
无法重现。 mymodel = glm(Winner~., data= data_train, family= binomial) 产生 Error in contrasts(*tmp*, value = contr.funs[1 + isOF[nn]]) : contrasts can be applied only to factors with 2 or more levels。请在 clean R 会话中测试您的代码。
你必须在predict中使用newdata而不是data：res2 <- predict(mymodel, newdata= data_test, type="response")
@ReninRK 我“只”收到一个警告：根据排名不足的拟合进行预测可能会产生误导。

标签： r regression predict

【解决方案1】：

当您使用predict 时，您必须使用newdata 而不是data 才能使用新数据集。

res2 <- predict(mymodel, newdata=data_test, type="response")

【讨论】：