CODEWITHSUNDEEP
rrecipetidymodels
Abdelouahed BEN MHAMED
Abdelouahed BEN MHAMED

Reputation: 157

how to add custom step in recipe

I want to transform my features for a machine learning model using a custom transformation. my function is :

step_customFunc <- function(x){ 1/(max(x+1) -x)}

Is there a way to add this in the pipeline of transformation using recipe and tidymodels like this way:

model_rec <- recipe(target ~ ., data) %>%
    step_customFunc(all_predictors)

Upvotes: 3

Views: 681

Answers (2)

EmilHvitfeldt
EmilHvitfeldt

Reputation: 3185

If your custom function is fairly simple, i.e. without arguments, you could also use step_mutate_at() to apply the function. This would be considerably less work than creating a new step.

library(recipes)
step_customFunc <- function(x){ 1 / (max(x + 1) - x)}

recipe(mpg ~ ., data = mtcars) %>%
  step_mutate_at(all_predictors(), fn = step_customFunc) %>%
  prep() %>%
  bake(new_data = NULL)
#> # A tibble: 32 x 11
#>      cyl    disp      hp  drat    wt  qsec    vs    am  gear  carb   mpg
#>    <dbl>   <dbl>   <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#>  1 0.333 0.00319 0.00442 0.493 0.263 0.134   0.5   1   0.5   0.2    21  
#>  2 0.333 0.00319 0.00442 0.493 0.282 0.145   0.5   1   0.5   0.2    21  
#>  3 0.2   0.00274 0.00412 0.481 0.244 0.189   1     1   0.5   0.125  22.8
#>  4 0.333 0.00465 0.00442 0.351 0.312 0.224   1     0.5 0.333 0.125  21.4
#>  5 1     0.00885 0.00621 0.360 0.335 0.145   0.5   0.5 0.333 0.143  18.7
#>  6 0.333 0.00403 0.00433 0.315 0.337 0.272   1     0.5 0.333 0.125  18.1
#>  7 1     0.00885 0.0110  0.368 0.350 0.124   0.5   0.5 0.333 0.2    14.3
#>  8 0.2   0.00306 0.00365 0.446 0.309 0.256   1     0.5 0.5   0.143  24.4
#>  9 0.2   0.00301 0.00415 0.498 0.305 1       1     0.5 0.5   0.143  22.8
#> 10 0.333 0.00327 0.00469 0.498 0.335 0.179   1     0.5 0.5   0.2    19.2
#> # … with 22 more rows

Created on 2021-03-18 by the reprex package (v0.3.0)

Upvotes: 4

Matt Kaye
Matt Kaye

Reputation: 520

I think you'll find some docs here: https://www.tidymodels.org/learn/develop/recipes/ under "A New Step Definition"

Upvotes: 2

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