R: coalescing a large data frame

Question

Say I create a data frame, foo:

foo <- data.frame(A=rep(NA,10),B=rep(NA,10))
foo$A[1:3] <- \"A\"
foo$B[6:10] <- \"B\"

Answer 1

You can use do.call(coalesce, ...), which is a simpler way to write a function call with a lot of arguments:

library(dplyr)
do.call(coalesce, foo)
# [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J"