From: Peter Dalgaard <p.dalgaard_at_biostat.ku.dk>

Date: Thu 18 Aug 2005 - 00:42:56 EST

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Aug 18 00:48:22 2005

Date: Thu 18 Aug 2005 - 00:42:56 EST

"Achaz von Hardenberg" <fauna@pngp.it> writes:

*> hi,
*

> sorry for a possibly naive question but I am a bit of a beginner in R programming...

*>
**> I wrote a function which simulates some data and performs two
**> different kinds of analyses on it. as an output I get the statistics
**> for the two analyses (t-values). Now I would like to have an other
**> function which reruns my first function say a 1000 times and
**> attaches the resulting statistics in a data.frame so that at the end
**> it contains 1000 rows with two columns for the two statistics I
**> calculated with my first function.
**>
**> I hope I was clear enugh and would be glad to anybody who can help me out!
*

replicate is a good start:

> replicate(10,t.test(rexp(10),mu=1)[c("statistic","p.value")])

[,1] [,2] [,3] [,4] [,5] [,6] statistic -1.552478 -1.09727 -2.053807 -1.671855 -0.1169578 0.1005037 p.value 0.1549645 0.3010120 0.07018008 0.1288855 0.9094619 0.9221477

[,7] [,8] [,9] [,10] statistic -0.1711356 -0.933484 0.3169710 -1.136498 p.value 0.867903 0.3749356 0.758495 0.2851029

As you see, the result is a 2xn matrix. If you really need a data frame, just use as.data.frame(t(....)), or (bypassing the matrix entirely):

> do.call("rbind",replicate(10,as.data.frame(

t.test(rexp(10),mu=1)[c("statistic","p.value")]), simplify=FALSE)) statistic p.value

t 0.32566430 0.7521223 t1 -1.22741479 0.2508023 t2 -1.66792987 0.1296757 t3 1.56440274 0.1521619 t4 0.63778111 0.5395015 t5 -1.03826715 0.3262346 t6 0.09337127 0.9276542 t7 0.90166085 0.3907282 t8 -0.78164107 0.4544958 t9 -0.39766367 0.7001452 -- O__ ---- Peter Dalgaard ุster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Aug 18 00:48:22 2005

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