[R] how to efficiently compute set unique?

From: G FANG <fanggangsw_at_gmail.com>
Date: Mon, 21 Jun 2010 18:06:58 -0700


Hi,

I want to get the unique set from a large numeric k by 1 vector, k is in tens of millions

when I used the matlab function unique, it takes less than 10 secs

but when I tried to use the unique in R with similar CPU and memory, it is not done in minutes

I am wondering, am I using the function in the right way?

dim(cntxtn)
[1] 13584763 1

uniqueCntxt = unique(cntxtn); # this is taking really long

Please advice.

Thanks,

Gang



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