Select should be able to rename variables

[hadley]

But what should select(sepal = c(Sepal.Width, Sepal.Length)) do?

• an error?
• add sepal as a prefix to existing names?
• create new names with sepal as prefix? (sepal1, sepal2)

[romainfrancois]

Maybe we can replace c by something else, which would control what to do. e.g.

select(sepal = prefix(Sepal.Width, Sepal.Length))

[hadley]

I think that's possible, but maybe challenging due to how evaluation currently works for select.

[romainfrancois]

Sure. Perhaps I was anticipating this: #172
I was just wondering if conceptually syntax like this would be interesting. Too bad we can't have functions in the rhs:

select( prefix(sepal) = c(Sepal.Width, Sepal.Length))

Could use := but then it looks like data.table refugee.

select( prefix(sepal) := c(Sepal.Width, Sepal.Length))

[hadley]

Well, you can define "prefix<-" <- function(x, value) {}...

[romainfrancois]

It does not make select( prefix(sepal) = c(Sepal.Width, Sepal.Length)) parsable.

> "prefix<-" <- function(x, value) {}
> parse( text = 'select( prefix(sepal) = c(Sepal.Width, Sepal.Length))' )
Erreur dans parse(text = "select( prefix(sepal) = c(Sepal.Width, Sepal.Length))") :
  <text>:1:23: '=' inattendu(e)
1: select( prefix(sepal) =

[hadley]

Oh bummer, I thought it would.