[R] Running *slow*

[Patrick Burns]

Probably most of the time you're waiting
for this you are in Circle 2 of 'The R
Inferno'.  If the values are numbers,
you might also be in Circle 1.

On 06/10/2011 13:37, Thomas wrote:
> Anyone got any hints on how to make this code more efficient? An early
> version (which to be fair did more than this one is) ran for 330 hours
> and produced no output.
>
> I have a two column table, Dat, with 12,000,000 rows and I want to
> produce a lookup table, ltable, in a 1 dimensional matrix with one copy
> of each of the values in Dat:
>
> for (i in 1:nrow(Dat))
> {
> for (j in 1:2)
> {
> #If next value is already in ltable, do nothing
> if (is.na(match(Dat[i,j], ltable))){ltable <- rbind(ltable,Dat[i,j])}
> }
> }
>
> but it takes forever to produce anything.
>
> Any advice gratefully received.
>
> Thomas
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Patrick Burns
pburns at pburns.seanet.com
twitter: @portfolioprobe
http://www.portfolioprobe.com/blog
http://www.burns-stat.com
(home of 'Some hints for the R beginner'
and 'The R Inferno')