tidymodels

Question

我正在尝试编写一个函数来适应使用 step_ns() 的配方的重新采样。出于某种原因，我收到错误消息：

Fold01: recipe: Error: Not all variables in the recipe are present in the supplied training set

依此类推。然后

警告信息： All models failed in [fit_resamples()]. See the .notes column.

这是我的代码：

compare_basis_exp_to_base_mod <- function (data, outcome, metric, ...) {

  outcome <- rlang::enquo(outcome)
  metric <- rlang::enquo(metric)
  
  pred_list <- colnames(data)
  
  outcome_str <- substring(deparse(substitute(outcome)), 2)
  outcome_str_id <- which(colnames(data) %in% outcome_str)
  
  predictor <- pred_list[-outcome_str_id]
  
  data <- data %>% 
    rename(prediction = !!outcome)

  res <- tibble(splits = list(), id = character(), .metrics = list(), 
                .notes = list(), .predictions = list(), pred = character())
  
  rec_without_splines <- recipe(prediction ~ ., data = data) %>%
    prep()
  
  rec_with_splines <- recipe(prediction ~ ., data = data) %>%
    step_ns(all_predictors(), ...) %>% 
    prep()
  
  folds_without_splines <- vfold_cv(juice(rec_without_splines), strata = prediction)
  
  folds_with_splines <- vfold_cv(juice(rec_with_splines), strata = prediction)
  

  mod <- linear_reg() %>% 
    set_engine("lm")

  mod_without_splines <- fit_resamples(mod,
                                       rec_without_splines,
                                       folds_without_splines,
                                       metrics = metric_set(!!metric),
                                       control = control_resamples(save_pred = TRUE)) %>%
    mutate(pred = "no_splines")
  
  mod_with_splines <- fit_resamples(mod,
                                    rec_with_splines,
                                    folds_with_splines,
                                    metrics = metric_set(!!metric),
                                    control = control_resamples(save_pred = TRUE)) %>%
    mutate(pred = "with_splines")

  res <- mod_without_splines %>%
    bind_rows(mod_with_splines)
  
  return (res)
}

基本上参数 data 包含两列 table 并且 outcome 是结果列的名称。除了使用这个函数（我只是在这里玩弄 tidymodels 因为我是新手）我只想了解是什么导致了这个错误以及如何修复它。评估 mod_with_splines.

时出现错误

遇到了类似的问题。但我不知道这是否与我的问题有关。在将它传递给 fit_resamples 之前，我不能不准备食谱。（或者我认为）

如有任何帮助，我们将不胜感激。谢谢。

Answer 1

您的问题来自于尝试在已经运行通过相同配方的数据集上应用配方。

如果我们假设预测变量是 X1 和 X2，那么 rec_with_splines 就是预期的那些变量。但由于 folds_with_splines 包含 rec_with_splines 的榨汁结果，因此 folds_with_splines 实际上包含 X1_ns_1、X1_ns_2、X2_ns_1 和 X2_ns_2。不是 X1 和 X2.

我建议使用 workflows 结合预处理和建模步骤。并将原始数据传递给 vfold_cv().

library(tidymodels)
compare_basis_exp_to_base_mod <- function (data, outcome, metric, ...) {

  outcome <- rlang::enquo(outcome)
  metric <- rlang::enquo(metric)
  
  pred_list <- colnames(data)
  
  outcome_str <- substring(deparse(substitute(outcome)), 2)
  outcome_str_id <- which(colnames(data) %in% outcome_str)
  
  predictor <- pred_list[-outcome_str_id]
  
  data <- data %>% 
    rename(prediction = !!outcome)
  
  rec_without_splines <- recipe(prediction ~ ., data = data) %>%
    prep()
  
  rec_with_splines <- recipe(prediction ~ ., data = data) %>%
    step_ns(all_predictors(), ...)
  
  mod <- linear_reg() %>% 
    set_engine("lm")
 
  wf_without_splines <- workflow() %>%
    add_recipe(rec_without_splines) %>%
    add_model(mod)
  
  wf_with_splines <- workflow() %>%
    add_recipe(rec_with_splines) %>%
    add_model(mod)
  
  data_folds <- vfold_cv(data, strata = prediction)

  mod_without_splines <- fit_resamples(wf_without_splines,
                                       data_folds,
                                       metrics = metric_set(!!metric),
                                       control = control_resamples(save_pred = TRUE)) %>%
    mutate(pred = "no_splines")
  
  mod_with_splines <- fit_resamples(wf_with_splines,
                                    data_folds,
                                    metrics = metric_set(!!metric),
                                    control = control_resamples(save_pred = TRUE)) %>%
    mutate(pred = "with_splines")

  res <- mod_without_splines %>%
    bind_rows(mod_with_splines)
  
  return (res)
}

res <- compare_basis_exp_to_base_mod(mtcars, mpg, rmse)

tidymodels - fit_resamples 使用 step_ns() 时出错

tidymodels - error in fit_resamples using step_ns()

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