[R] Adding variables

[Gabor Grothendieck]

with(attenu, mag + as.numeric(station))

is nearly twice as fast:

> system.time(for(i in 1:1000) with(attenu, mag + as.numeric(station)))
   user  system elapsed
   0.05    0.02    0.06

> system.time(for(i in 1:1000) rowSums(cbind(mag, station)))
   user  system elapsed
   0.09    0.00    0.10

See ?system.time, ?Rprof and http://code.google.com/p/rbenchmark/
for timing commands.

On Sat, Sep 26, 2009 at 11:16 AM, tzygmund mcfarlane
<tzygmund at googlemail.com> wrote:
> Hi,
>
> For very large matrices, is this the most efficient way to add two
> variables together?
>
> #############################
> attach(attenu)
> new<-rowSums(cbind(mag, station))
> #############################
>
> Also, could I be directed to some resources for working with very
> large datasets?
>
> Thanks
>
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