Allow named character vector in select, to rename variables

[strengejacke]

library(datawizard)
data(mtcars)

data_select(mtcars, c(neu = "mpg", alt = "cyl", hoho = "wt")) |> head()
#>                    neu alt  hoho
#> Mazda RX4         21.0   6 2.620
#> Mazda RX4 Wag     21.0   6 2.875
#> Datsun 710        22.8   4 2.320
#> Hornet 4 Drive    21.4   6 3.215
#> Hornet Sportabout 18.7   8 3.440
#> Valiant           18.1   6 3.460

data_select(mtcars, c(neu = "mpg", "cyl", hoho = "wt")) |> head()
#>                    neu cyl  hoho
#> Mazda RX4         21.0   6 2.620
#> Mazda RX4 Wag     21.0   6 2.875
#> Datsun 710        22.8   4 2.320
#> Hornet 4 Drive    21.4   6 3.215
#> Hornet Sportabout 18.7   8 3.440
#> Valiant           18.1   6 3.460

^{Created on 2024-06-07 with reprex v2.1.0}

[etiennebacher]

Thanks, can you also add tests for:

• what happens when the new name already exists in the data?
• what happens if the new name is used in exclude?

[strengejacke]

what happens when the new name already exists in the data?

It can't already exist in the data, because only the selected variables are returned. Thus, the case would be that a new name is chosen twice or more often. I'd say this should give an error?

what happens if the new name is used in exclude?

select and exclude are processed before we check names, so any names used in exclude will be ignored for now (it also wouldn't make sense to specify a value in exclude that matches a new name, so the selected variable will be excluded, too - at least it wouldn't make sense in interactive use).

What would you suggest? Check earlier and also exclude those variables?

[etiennebacher]

I'd say this should give an error?

Agreed, I'm fine with the current changes

What would you suggest? Check earlier and also exclude those variables?

My second point was more about whether the following works, and it does:

library(datawizard)

data_select(head(mtcars), c(drat = "mpg"), exclude = "drat")
#>                   drat
#> Mazda RX4         21.0
#> Mazda RX4 Wag     21.0
#> Datsun 710        22.8
#> Hornet 4 Drive    21.4
#> Hornet Sportabout 18.7
#> Valiant           18.1

We could add a test for this situation (if you agree with the current behavior)

[etiennebacher]

Apart from adding a test as mentioned in my comment above, this looks good to me, thanks!