Fill values in one vector conditioned on values in another vector

Question

I have two data frames with two different dimensions :

1:

head(x)
   Year GDP_deflator
1  1825           NA
2  1826           NA
3  1827           NA
4           


        

Answer 1

One possibility is to use match:

x$GDP_deflator <- dataDef$GDP_deflator[match(x$Year, dataDef$Year)]