On 09.06.2011 18:09, R Help wrote:
That wouldn't work because the seed is for the first iteration. Random numbers are generated by a seed, after which the seed changes (I don't know the mechanism for changing the seed in R, but it's static) That means that, if you set the seed to 1001, and then run runif function 50 times, you'll get 50 different sets of random numbers. If you reset the seed to 1001 and then run runif again, the result will be the same as data[[1]], not [[23]]. And you can't just set the seed to 1023 because that's not how the seed changes. I think Jim's suggestion was the best. I was thinking of that but I couldn't remember how to extract the seed.
Well set.seed() actually generates a seed. See ?set.seed that points us to .Random.seed (and relevant references!) which contains the actual current seed.
Uwe Ligges
Sam On Thu, Jun 9, 2011 at 12:23 PM, Samuel Le<[email protected]> wrote:What about: set.seed(1001) total<- 0 data<- vector("list", 30) for(i in 1:30) { data[[i]]<- runif(50) } set.seed(1001) data[[23]]<- runif(50) HTH Samuel -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Soyeon Kim Sent: 09 June 2011 16:15 To: r-help Subject: [R] set.seed and for loop Dear All, This is hard to describe so I made a simple example. set.seed(1001) total<- 0 data<- vector("list", 30) for(i in 1:30) { data[[i]]<- runif(50) } Let's call a data set runif(50). While the for loop is running, 100 data sets are generated. I want to restore 23th data set (the data set generated in 23th for loop) without the loop. I've tried set.seed(1023) runif(50) but this is different data from the data set gotten from 23th for loop. How can I get 23th data set without the loop? Thank you, Soyeon ______________________________________________ [email protected] 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. __________ Information from ESET NOD32 Antivirus, version of virus signature database 6193 (20110609) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signature database 6193 (20110609) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ______________________________________________ [email protected] 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.______________________________________________ [email protected] 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.
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