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
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--
Patrick Burns
pbu...@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')
______________________________________________
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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.
