What's wrong with as.numeric in R? [duplicate]

Answer 1

The documentation at ?factor states:

To transform a factor f to approximately its original numeric values, as.numeric(levels(f))[f] is recommended and slightly more efficient than as.numeric(as.character(f)).

So the following works as well:

as.numeric(levels(my_vec))[my_vec]

Answer 2

Your vector is a factor. This question has been asked quite a few times, ex: here, here, here. In order to convert a factor to numeric, you'll have to convert to character first. Try:

as.numeric(as.character(my_vec))