Perhaps you can convert your matrices to data frames as in: mapply(t.test,as.data.frame(myData1),as.data.frame(myData2)) to test by column and
mapply(t.test,as.data.frame(t(myData1)),as.data.frame(t(myData2))) to test by row? ----- Original Message ---- From: Gang Chen <gangch...@gmail.com> To: Henrique Dallazuanna <www...@gmail.com> Cc: r-h...@stat.math.ethz.ch Sent: Tuesday, January 6, 2009 10:10:44 AM Subject: Re: [R] Using apply for two datasets Thanks a lot for the quick help! mapply() seems promising. However, mapply(t.test, myData1, myData2) would not work, so how can I specify the margin in mapply() which function t.test() will be applied over? For example, I specify the 2nd dimension (column) in apply(myData1, 2, t.test) to run one-sample t-test. Is there a way I can achieve the same with mapply()? Thanks again, Gang On Tue, Jan 6, 2009 at 12:34 PM, Henrique Dallazuanna <www...@gmail.com> wrote: > I think that you can use mapply for this. > > On Tue, Jan 6, 2009 at 3:24 PM, Gang Chen <gangch...@gmail.com> wrote: >> >> I can run one-sample t-test on an array, for example a matrix myData1, >> with the following >> >> apply(myData1, 2, t.test) >> >> Is there a similar fashion using apply() or something else to run >> 2-sample t-test with datasets from two groups, myData1 and myData2, >> without looping? >> >> TIA, >> Gang ______________________________________________ R-help@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. ______________________________________________ R-help@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.