[R] Very slow using S4 classes

[Uwe Ligges]

On 10.09.2011 17:08, André Rossi wrote:
> Hi everybody!
>
> I'm creating an object of a S4 class that has two slots: ListExamples, which
> is a list, and idx, which is an integer (as the code below).
>
> Then, I read a data.frame file with 10000 (ten thousands) of lines and 10
> columns, do some pre-processing and, basically, I store each line as an
> element of a list in the slot ListExamples of the S4 object. However, many
> operations after this take a considerable time.
>
> Can anyone explain me why dois it happen? Is it possible to speed up an
> script that deals with a big number of data (it might be data.frame or
> list)?

0. This sounds inefficient even when not using S4 classes. You may want 
to reconsider how to solve your problem in another way.

1. A first step for speedup would be not to use S4 objects.

2. If you really want to use some S4 object to store the stuff, try to 
assign to a list (that is not wrapped within an S4 class) first and then 
assign the whole list into your Buffer object.

Best,
Uwe Ligges


>
> Thank you,
>
> André Rossi
>
> setClass("Buffer",
>      representation=representation(
>          Listexamples = "list",
>          idx = "integer"
>      )
> )
>
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>
>
>
>
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