How to replace NA with most recent non-NA by group? [duplicate]

Answer 1

Here is a base R solution. The fill function invokes ave using na.omit(x)[1] as in Richie Cotton's solution.

fill <- function(...) ave(..., FUN = function(x) na.omit(x)[1])
transform(df, birthplace = fill(birthplace, name), age = fill(age, name))

Note: This also works with na.locf. Replace fill with:

library(zoo)
fill <- function(...) ave(..., FUN = function(x) na.locf(x, na.rm = FALSE))