R group by, counting non-NA values

Question

I have a dataframe that has a scattering of NA\'s

toy_df
# Y  X1 X2 Label
# 5  3  3  A
# 3  NA 2  B
# 3  NA NA C
# 2  NA 6  B

I want to gr

Answer 1

Or in base R

aggregate(toy_df[,1:3], by=list(toy_df$Label), FUN=function(x) { sum(!is.na(x))})