dplyr summarise when function return is vector-valued?

Question

The dplyr::summarize() function can apply arbitrary functions over the data, but it seems that function must return a scalar value. I\'m curious if there is a reas

Answer 1

This is why I still love plyr::ddply():

library(plyr)
f <- function(z) setNames(coef(lm(x ~ y, z)), c("a", "b"))
ddply(df, ~ group, f)
#   group           a          b
# 1     A   0.5213133 0.04624656
# 2     B   0.3020656 0.01450137
# 3     C   0.2189537 0.22998823