I create a lot of columns via summarize and delete columns that I don’t need in a second step. Another option would be to create each column separately and then join them using join, which is probably not faster.

The program code currently looks like this:

Data <- Data %>%
    group_by_at(group_by_Vektor) %>%
    summarize(var_1 = sum(var_1), 
              var_2 = sum(var_2), 
              ...
              var_n = sum(var_n),
             .groups = 'drop')
if (!condition_1) {
    Data <- select(Data, -var_1))
}
if (!condition_2) {
    Data <- select(Data, -var_2))
}
...
if (!condition_n) {
    Data <- select(Data, -var_2))
}

I am looking for something like this:

Data <- Data %>%
    group_by_at(group_by_Vektor) %>%
    summarize(if(condition_1, var_1 = sum(var_1)), 
              if(condition_2, var_2 = sum(var_2), 
              ...
              if(condition_n, var_n = sum(var_n)),
             .groups = 'drop')

Thank you very much!
Roland