Hi,
I don't know why but my columns "annee" where I use the groupby is rename in a bad version :
df <- data.frame(subset(data))[,c("nb_aaa", "nb_bbb")] %>%
group_by(data[,c("annee")]) %>%
summarise_each(funs = sum)
It works but my output is :

how can I have only "annee" ?? and not data[,c("annee")]
Thanks