I'm learning R and I'm curious... I need a function that does this:
> fillInTheBlanks(c(1, NA, NA, 2, 3, NA, 4))
[1] 1 1 1 2 3 3 4
> fillInTheBlanks(c(1, 2, 3, 4))
[1] 1 2 3 4
and I produced this one... but I suspect there's a more R way to do this.
fillInTheBlanks <- function(v) {
## replace each NA with the latest preceding available value
orig <- v
result <- v
for(i in 1:length(v)) {
value <- v[i]
if (!is.na(value))
result[i:length(v)] <- value
}
return(result)
}
Package zoo
has a function na.locf()
:
R> library("zoo")
R> na.locf(c(1, 2, 3, 4))
[1] 1 2 3 4
R> na.locf(c(1, NA, NA, 2, 3, NA, 4))
[1] 1 1 1 2 3 3 4
na.locf
: Last Observation Carried Forward;
Generic function for replacing each ‘NA’ with the most recent non-‘NA’ prior to it.
See the source code of the function na.locf.default
, it doesn't need a for
-loop.