Clean solution to avoid error caused by selection

Question

I try to do something like

df[<very-long-and-complicated-selection>,]$foo <- "bar"

This works well, if there are rows matching the selection.

If not I get an error message

Error in $<-.data.frame(*tmp*, "foo", value = "bar") :
replacement has 1 row, data has 0

However, my code is designed in a way, where no matching is possible.

Is there a clean, short and easy solution to avoid these (and only these) errors?

Answer 1

Use

df[<very-long-and-complicated-selection>, "foo"] <- "bar"

ie, make the assignment into the dataframe treating it as a 2-dimensional object, rather than as a list.