Error in createDummyFeatures.data.frame(df, cols = df$var)

[decenwang]

Hi All,

I am a new learner, I prefer using mlr to do a classification task, when I use the "createDummyFeatures(df, cols = df$var)" function to generate the dummy variables, there's an error "Error in createDummyFeatures.data.frame(df, cols = df$var) :
Assertion on 'cols' failed: Must be a subset of the empty set, i.e. also empty." I tried to get a solution on the internet, but I failed again. I followed someone's solution, running "df <- data.frame(var = sample(c("A", "B", "C"), 10, replace = TRUE))", and then "createDummyFeatures(df, cols = "var")". I got the error, also, when I used my data, I got the same error. Could you please help me out ? thanks a lot!

Best,
Decen

[pat-s]

Hi,

thanks for posting your issue here.
Please provide a reproducible example, preferably using the reprex package.

[pat-s]

Again: Please provide a valid reprex with a code snippet AND format your code so that is readable. Please do not insert screenshots of error message. Thanks.

I see you tried using the {reprex} package but did not use it correctly. Please read again how to use it. Thanks.

[decenwang]

Hi there,

Sorry for trouble, this is the first time I use "reprex()", I just wanna know how the error generated in my code and how I can crack it? Thanks a lot!

df <- data.frame(var = sample(c("A", "B", "C"), 10, replace = TRUE))
df
#>    var
#> 1    A
#> 2    C
#> 3    C
#> 4    A
#> 5    C
#> 6    B
#> 7    A
#> 8    C
#> 9    B
#> 10   A
createDummyFeatures(df, cols = "var")
#> Error in createDummyFeatures(df, cols = "var"): could not find function "createDummyFeatures"

^{Created on 2020-08-24 by the reprex package (v0.3.0)}

Session info

devtools::session_info()
#> - Session info ---------------------------------------------------------------
#>  setting  value                         
#>  version  R version 4.0.0 (2020-04-24)  
#>  os       Windows 10 x64                
#>  system   x86_64, mingw32               
#>  ui       RTerm                         
#>  language en                            
#>  collate  Chinese (Simplified)_China.936
#>  ctype    Chinese (Simplified)_China.936
#>  tz       Asia/Taipei                   
#>  date     2020-08-24                    
#> 
#> - Packages -------------------------------------------------------------------
#>  package     * version date       lib source        
#>  assertthat    0.2.1   2019-03-21 [1] CRAN (R 4.0.0)
#>  backports     1.1.7   2020-05-13 [1] CRAN (R 4.0.0)
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#>  htmltools     0.5.0   2020-06-16 [1] CRAN (R 4.0.0)
#>  knitr         1.29    2020-06-23 [1] CRAN (R 4.0.2)
#>  magrittr      1.5     2014-11-22 [1] CRAN (R 4.0.0)
#>  memoise       1.1.0   2017-04-21 [1] CRAN (R 4.0.2)
#>  pkgbuild      1.0.8   2020-05-07 [1] CRAN (R 4.0.0)
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#>  ps            1.3.3   2020-05-08 [1] CRAN (R 4.0.0)
#>  R6            2.4.1   2019-11-12 [1] CRAN (R 4.0.0)
#>  remotes       2.1.1   2020-02-15 [1] CRAN (R 4.0.2)
#>  rlang         0.4.6   2020-05-02 [1] CRAN (R 4.0.0)
#>  rmarkdown     2.3     2020-06-18 [1] CRAN (R 4.0.2)
#>  rprojroot     1.3-2   2018-01-03 [1] CRAN (R 4.0.0)
#>  sessioninfo   1.1.1   2018-11-05 [1] CRAN (R 4.0.2)
#>  stringi       1.4.6   2020-02-17 [1] CRAN (R 4.0.0)
#>  stringr       1.4.0   2019-02-10 [1] CRAN (R 4.0.0)
#>  testthat      2.3.2   2020-03-02 [1] CRAN (R 4.0.0)
#>  usethis       1.6.1   2020-04-29 [1] CRAN (R 4.0.2)
#>  withr         2.2.0   2020-04-20 [1] CRAN (R 4.0.0)
#>  xfun          0.15    2020-06-21 [1] CRAN (R 4.0.2)
#>  yaml          2.2.1   2020-02-01 [1] CRAN (R 4.0.0)
#> 
#> [1] D:/Program Files/R/R-4.0.0/library

[pat-s]

You either need to call library(mlr) first or prefix the namespace via mlr::.

[decenwang]

You either need to call library(mlr) first or prefix the namespace via mlr::.

Sure, before I did this, I load mlr, even mlr3. but I got the error like that in the graph. Anyway, I will try the built-in "model-matrix" function. Thanks.

[pat-s]

In your reprex you did not and I just commented on that error.

Learning to make a good reprex is a valuable skill. Often enough you find a solution yourself while trying to make one.

[pat-s]

Closing due to missing reprex.

[jakob-r]

The problem is that createDummyFeatures() needs factor columns and not character columns.

library(mlr)
df <- data.frame(var = sample(c("A", "B", "C"), 10, replace = TRUE), stringsAsFactors=TRUE)
createDummyFeatures(df, cols = "var")