step_meanimpute
creates a specification of a recipe step that will
substitute missing values of numeric variables by the training set mean of
those variables.
step_meanimpute( recipe, ..., role = NA, trained = FALSE, means = NULL, trim = 0, skip = FALSE, id = rand_id("meanimpute") ) # S3 method for step_meanimpute tidy(x, ...)
recipe | A recipe object. The step will be added to the sequence of operations for this recipe. |
---|---|
... | One or more selector functions to choose which variables are
affected by the step. See |
role | Not used by this step since no new variables are created. |
trained | A logical to indicate if the quantities for preprocessing have been estimated. |
means | A named numeric vector of means. This is |
trim | The fraction (0 to 0.5) of observations to be trimmed from each end of the variables before the mean is computed. Values of trim outside that range are taken as the nearest endpoint. |
skip | A logical. Should the step be skipped when the
recipe is baked by |
id | A character string that is unique to this step to identify it. |
x | A |
An updated version of recipe
with the new step added to the
sequence of existing steps (if any). For the tidy
method, a tibble with
columns terms
(the selectors or variables selected) and model
(the mean
value).
step_meanimpute
estimates the variable means from the data used
in the training
argument of prep.recipe
. bake.recipe
then applies the
new values to new data sets using these averages.
library(modeldata) data("credit_data") ## missing data per column vapply(credit_data, function(x) mean(is.na(x)), c(num = 0))#> Status Seniority Home Time Age Marital #> 0.0000000000 0.0000000000 0.0013471037 0.0000000000 0.0000000000 0.0002245173 #> Records Job Expenses Income Assets Debt #> 0.0000000000 0.0004490346 0.0000000000 0.0855410867 0.0105523125 0.0040413112 #> Amount Price #> 0.0000000000 0.0000000000set.seed(342) in_training <- sample(1:nrow(credit_data), 2000) credit_tr <- credit_data[ in_training, ] credit_te <- credit_data[-in_training, ] missing_examples <- c(14, 394, 565) rec <- recipe(Price ~ ., data = credit_tr) impute_rec <- rec %>% step_meanimpute(Income, Assets, Debt) imp_models <- prep(impute_rec, training = credit_tr) imputed_te <- bake(imp_models, new_data = credit_te, everything()) credit_te[missing_examples,]#> Status Seniority Home Time Age Marital Records Job Expenses Income #> 28 good 15 owner 36 43 married no fixed 75 251 #> 688 good 2 rent 60 32 married no partime 87 115 #> 1002 good 21 rent 60 39 married no fixed 124 191 #> Assets Debt Amount Price #> 28 4000 0 1800 2557 #> 688 2000 0 1250 1517 #> 1002 2000 0 2000 2536#> # A tibble: 3 x 14 #> Status Seniority Home Time Age Marital Records Job Expenses Income #> <fct> <int> <fct> <int> <int> <fct> <fct> <fct> <int> <int> #> 1 good 15 owner 36 43 married no fixed 75 251 #> 2 good 2 rent 60 32 married no part… 87 115 #> 3 good 21 rent 60 39 married no fixed 124 191 #> # … with 4 more variables: Assets <int>, Debt <int>, Amount <int>, Price <int>#> # A tibble: 3 x 3 #> terms model id #> <chr> <dbl> <chr> #> 1 Income NA meanimpute_Hlm2y #> 2 Assets NA meanimpute_Hlm2y #> 3 Debt NA meanimpute_Hlm2y#> # A tibble: 3 x 3 #> terms model id #> <chr> <int> <chr> #> 1 Income 142 meanimpute_Hlm2y #> 2 Assets 5378 meanimpute_Hlm2y #> 3 Debt 364 meanimpute_Hlm2y