In R, Merge two data frames, fill down the blanks

Question

Say I have these two data frames:

big.table <- data.frame(\"idx\" = 1:100)

small.table <- data.frame(\"idx\" = sample(1:100, 10), \"color\" = sample(c         


        

Answer 1

It sounds like you need na.locf from the package zoo (stands for last observation carried forward):

library(zoo)
tbl <- merge(small.table, big.table, by = "idx", all.y=TRUE)
tbl$color2 <- na.locf(tbl$color,na.rm = FALSE)