I have the following two similar dataframes:

d1<-data.frame(TNR=c(1,2,3,4,5,6,7),EP=c(0,3,1,2,NA,NA,NA))
d2<-data.frame(TNR=c("E",1,3,5,100), EP=c(NA,NA,NA,NA,NA))

In d2 the vector "EP" is empty and i want to fill it with the data from d1$EP, where the vectors TNR overlap with each other. Where they don’t overlap I want to keep d2 and not d1.

The result should look something like that:

d3<-data.frame(TNR=c("E",1,3,5,100),EP=c(NA,0,1,NA,NA))

I tried the following approach with ifelse and %in%:

d3<-data.frame(TNR=ifelse(test=d1$TNR %in% d2$TNR, yes=d2$EP, no=NA),
               EP=ifelse(test=d1$TNR %in% d2$TNR, yes=d1$EP, no="")) 
#remove rows where TNR is NA

d4=d3[!is.na(d1$baumnummer),]

However, the result is that EP is inserted in the wrong order and it seems to delete more rows than I anticipated because the resulting dataframe is shorter than d2

>Solution :

Is that OK?

d2$EP <- d1[match(x = d2$TNR, table = d1$TNR), ]$EP