g2 = c(1, 1, 1, 2, 2), aa = 1:5, bb = 5:1) group_sum_ng <- function(df, by) { df %>% group_by(by) %>% summarise_all(sum) } group_sum_ng(df, g1) grouped_df_impl(data, unname(vars), drop) ͰΤϥʔ: Column `by` is unknown • dplyr࠶ೖʢTidyevalฤʣhttps://speakerdeck.com/yutannihilation/dplyrzai-ru-men-tidyevalbian CZͰࢦఆͨ͠ྻͰ άϧʔϓԽ͍ͨ͠