recipes converts strings to factors without being asked to.

[SimonCoulombe]

Hi!
Back in the days, one needed to use recipes::string2factor() to convert strings to factor. Now it is all done without asking.
Is it the expected behaviour?

library(recipes)
library(nycflights13)

myrecipes  <-  recipes::recipe(
  formula = arr_delay ~ carrier + distance,
  data = flights)
prepped_recipe <- recipes::prep(myrecipes, flights)

baked_data  <- recipes::bake(prepped_recipe, new_data = flights)


###flights %>% select(carrier) %>% glimpse
####carrier <chr> "UA", "UA"

### baked_data %>% glimpse
###  carrier   <fct> UA, UA,

Here is my sessioninfo() if it is not the expected behaviour:

> sessioninfo::session_info()
- Session info --------------------------------------------------------------------------------------------------------
 setting  value                       
 version  R version 3.6.2 (2019-12-12)
 os       Windows 10 x64              
 system   x86_64, mingw32             
 ui       RStudio                     
 language (EN)                        
 collate  French_Canada.1252          
 ctype    French_Canada.1252          
 tz       America/New_York            
 date     2021-10-13                  

- Packages ------------------------------------------------------------------------------------------------------------
 package        * version    date       lib source        
 assertthat       0.2.1      2019-03-21 [1] CRAN (R 3.6.2)
 class            7.3-15     2019-01-01 [1] CRAN (R 3.6.2)
 cli              2.3.1      2021-02-23 [1] CRAN (R 3.6.2)
 crayon           1.3.4      2017-09-16 [1] CRAN (R 3.6.2)
 DBI              1.1.0      2019-12-15 [1] CRAN (R 3.6.2)
 dplyr          * 1.0.4      2021-02-02 [1] CRAN (R 3.6.3)
 ellipsis         0.3.0      2019-09-20 [1] CRAN (R 3.6.2)
 fansi            0.4.1      2020-01-08 [1] CRAN (R 3.6.2)
 generics         0.1.0      2020-10-31 [1] CRAN (R 3.6.3)
 glue             1.4.2      2020-08-27 [1] CRAN (R 3.6.3)
 gower            0.2.1      2019-05-14 [1] CRAN (R 3.6.1)
 ipred            0.9-9      2019-04-28 [1] CRAN (R 3.6.2)
 lattice          0.20-38    2018-11-04 [1] CRAN (R 3.6.2)
 lava             1.6.6      2019-08-01 [1] CRAN (R 3.6.2)
 lifecycle        1.0.0      2021-02-15 [1] CRAN (R 3.6.2)
 lubridate        1.7.4      2018-04-11 [1] CRAN (R 3.6.2)
 magrittr         1.5        2014-11-22 [1] CRAN (R 3.6.2)
 MASS             7.3-51.4   2019-03-31 [1] CRAN (R 3.6.2)
 Matrix           1.2-18     2019-11-27 [1] CRAN (R 3.6.2)
 nnet             7.3-12     2016-02-02 [1] CRAN (R 3.6.2)
 nycflights13   * 1.0.1      2019-09-16 [1] CRAN (R 3.6.2)
 palmerpenguins * 0.1.0      2020-07-23 [1] CRAN (R 3.6.3)
 pillar           1.4.3      2019-12-20 [1] CRAN (R 3.6.2)
 pkgconfig        2.0.3      2019-09-22 [1] CRAN (R 3.6.2)
 prodlim          2019.11.13 2019-11-17 [1] CRAN (R 3.6.2)
 purrr            0.3.3      2019-10-18 [1] CRAN (R 3.6.2)
 R6               2.4.1      2019-11-12 [1] CRAN (R 3.6.2)
 Rcpp             1.0.3      2019-11-08 [1] CRAN (R 3.6.2)
 recipes        * 0.1.16     2021-04-16 [1] CRAN (R 3.6.3)
 rlang            0.4.10     2020-12-30 [1] CRAN (R 3.6.3)
 rpart            4.1-15     2019-04-12 [1] CRAN (R 3.6.2)
 rstudioapi       0.11       2020-02-07 [1] CRAN (R 3.6.2)
 sessioninfo      1.1.1      2018-11-05 [1] CRAN (R 3.6.2)
 stringi          1.4.6      2020-02-17 [1] CRAN (R 3.6.2)
 stringr          1.4.0      2019-02-10 [1] CRAN (R 3.6.2)
 survival         3.1-8      2019-12-03 [1] CRAN (R 3.6.2)
 tibble           2.1.3      2019-06-06 [1] CRAN (R 3.6.2)
 tidyr            1.0.2      2020-01-24 [1] CRAN (R 3.6.2)
 tidyselect       1.1.0      2020-05-11 [1] CRAN (R 3.6.3)
 timeDate         3043.102   2018-02-21 [1] CRAN (R 3.6.2)
 utf8             1.1.4      2018-05-24 [1] CRAN (R 3.6.2)
 vctrs            0.3.6      2020-12-17 [1] CRAN (R 3.6.3)
 withr            2.4.1      2021-01-26 [1] CRAN (R 3.6.3)

[EmilHvitfeldt]

prep() defaults to turning strings to factors, you can turn that off by setting strings_as_factors = FALSE in prep()

library(recipes)
library(nycflights13)

myrecipes  <-  recipes::recipe(
  formula = arr_delay ~ carrier + distance,
  data = flights)
prepped_recipe <- recipes::prep(myrecipes, flights, strings_as_factors = FALSE)

recipes::bake(prepped_recipe, new_data = flights)
#> # A tibble: 336,776 × 3
#>    carrier distance arr_delay
#>    <chr>      <dbl>     <dbl>
#>  1 UA          1400        11
#>  2 UA          1416        20
#>  3 AA          1089        33
#>  4 B6          1576       -18
#>  5 DL           762       -25
#>  6 UA           719        12
#>  7 B6          1065        19
#>  8 EV           229       -14
#>  9 B6           944        -8
#> 10 AA           733         8
#> # … with 336,766 more rows

^{Created on 2021-10-13 by the reprex package (v2.0.1)}

[SimonCoulombe]

oh! I didnt see any parameters in recipe()... didnt think to check prep().

thanks for your help!

[juliasilge]

Thanks so much for your question here! FYI we are planning to move where the strings_as_factors arg lives, from prep() to the recipe itself (see #331, #715, and unfortunately others). We agree that it is not ideal currently.

[github-actions]

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