Proposition for changing the error message in group_by when using unknown columns

[Sade154]

Hello,

When we use group_by with a wrong column name we get this :

library(dplyr)
group_by(iris, wrong_name_of_variable)
# Error: index out of bounds

I think, it would be better to have an error message like with filter which is more helpful (especially when we deal with many variables ):

filter(iris, wrong_name_of_variable)
Error: unknown column : wrong_name_of_variable

KR

[romainfrancois]

@Sade154 can you wrap you code with "```" please.