[datatable-help] can one name a collection of columns by specifying just the first and the last column

[Arunkumar Srinivasan]

I had the same reaction when I found out ‘subset’ already did this :-).
I’ve the same impression that it’s a bit odd, even though some people prefer it.. 

-- 
Arun

On 10 Feb 2015 at 19:39:29, Chris Neff (caneff at gmail.com) wrote:

Wow, didn't realize that worked! So there is precedent then.  It just looks funny to me, but you are right it is easily avoided.  I just didn't want to see more divergence from subset and data.frame logic, but since this already works with subset that's fine.

On Tue Feb 10 2015 at 1:34:03 PM Arunkumar Srinivasan <aragorn168b at gmail.com> wrote:
Chris,

But what’s the problem? You can simply not use it?
It’s not that uncommon. `base::subset()` does this.

-- 
Arun

On 10 Feb 2015 at 19:31:43, Chris Neff (caneff at gmail.com) wrote:

I don't like this idea. It adds extra that it doesn't need to.  Doing it with column numbers is more straightforward, and if all you have is names you can get numbers by doing match() or whatever and then getting the sequence with seq(). Having a sequence of column names is odd.

On Tue Feb 10 2015 at 1:28:25 PM Arunkumar Srinivasan <aragorn168b at gmail.com> wrote:
Farrel,

It could be useful. Please file an issue on the github project page. Thanks.

-- 
Arun

On 10 Feb 2015 at 01:08:46, Farrel Buchinsky (fjbuch at gmail.com) wrote:

So lets say one has a data.table with the following columns

first.name, last.name, height, weight, shoe.size, eye.color, hair.length, appendage.size, ear.length

If one wanted to just include weight through hair.length one would have to go something such as this

dt[,list(weight, shoe.size, eye.color, hair.length)]

Is there a way to do something along the lines of

dt[,list(weight...hair.length)]

If so, can you direct me to the documentation? If not can you build it? Is it difficult? Some data.tables have many columns.

Thanking you in anticipation.

Farrel
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