[datatable-help] use of data.table in an S4 class

[Steve Lianoglou]

Hi,

> # create a TestObj
> lala <- new("TestObj", id = "test", dt = data.table(a=1:10, b=11:20))
>
> # accessing the data.table slot results in a copy :-(
> lala at dt <- lala at dt[, c1 := a + b]

You are reassigning to the object here, what if you were to do this:

R> lala at dt[, c1 := a + b]

Accessing S4 object directory via their slot (ie using @) is
discouraged, but I'm not how it would work if you did the same using a
function. For example you might create a function `dt` that returns
the object in the @dt slot then work on it directly:

R> dt(lala)[, c1 := a + b]

Perhaps you can play with those and let us know if either is satisfactory?

-steve

-- 
Steve Lianoglou
Computational Biologist
Genentech