I've been using get() in a loop to manipulate a column j by i with reference to multiple other columns.

I wonder if there is a faster/more efficient way? Any performance considerations?

Here a minimal example of the type of operation I have in mind:

```
require(data.table) # version 1.12.8
dt = data.table(v1=c(1,2,NA),v2=c(0,0,1),v3=c(0,0,0))
for (i in 1:2){
     dt[ is.na(get(paste0('v',i))), (paste0('v',i)):= get(paste0('v',i+1))+2 ][]
}

```

The actual tables I do this with are much larger (~5 mio rows, ~300 columns). 

I'd highly appreciate any thoughts.