can I use pivot_wider to sum?

[Erica]

when I use the code

df%>% pivot_wider(id_cols=id, names_from="group", values_from="value")

I get a dataframe where each group column contains a list of values from the value column.... when I use

df%>% pivot_wider(id_cols=id, names_from="group", values_from="value", values_fn=sum())

I get Error in values_fn[[value]] : subscript out of bounds

What am I missing? Thanks!

[joels]

Remove the parentheses from sum() and it should work:

df%>% 
   pivot_wider(id_cols=id, names_from="group", values_from="value", 
               values_fn=sum)

[Erica]

I get a different error when I do it that way:
Error in values_fn[[value]] : object of type 'builtin' is not subsettable

Any idea what it means?

[joels]

I think we'll need a reproducible example (data and code that we can copy and paste to reproduce the problem you're having) to figure out what's going on. For now, here's an example that works:

library(tidyverse)

iris %>% 
  pivot_wider(names_from=Species, values_from=where(is.numeric),
              values_fn=sum) %>% 
  as.data.frame()
#>   Sepal.Length_setosa Sepal.Length_versicolor Sepal.Length_virginica
#> 1               250.3                   296.8                  329.4
#>   Sepal.Width_setosa Sepal.Width_versicolor Sepal.Width_virginica
#> 1              171.4                  138.5                 148.7
#>   Petal.Length_setosa Petal.Length_versicolor Petal.Length_virginica
#> 1                73.1                     213                  277.6
#>   Petal.Width_setosa Petal.Width_versicolor Petal.Width_virginica
#> 1               12.3                   66.3                 101.3

^{Created on 2020-07-23 by the reprex package (v0.3.0)}