Dear r-help, I have an array a1 with dimensions [1:660,1:65,1:25] I would like the first dimension to be the last one. That is I want and array [1:65,1:25,1:660] The only way to do this, I know, is tmp.a<-array(dim=dim(a1)[c(2,3,1)]) for(i in 1:dim(a1)[1]) tmp.a[,,i]<-a1[i,,] a1<-tmp.a rm(tmp.a) Is it possible to avoid 'for' loop here? Thank you! --- Best regards, Wladimir mailto:wl at eimb.ru
how to reshape an array avoiding for loops
4 messages · Vladimir Eremeev, Bert Gunter, Peter Dalgaard +1 more
?aperm -- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA "The business of the statistician is to catalyze the scientific learning process." - George E. P. Box
-----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Wladimir Eremeev Sent: Tuesday, August 16, 2005 2:12 PM To: r-help at stat.math.ethz.ch Subject: [R] how to reshape an array avoiding for loops Dear r-help, I have an array a1 with dimensions [1:660,1:65,1:25] I would like the first dimension to be the last one. That is I want and array [1:65,1:25,1:660] The only way to do this, I know, is tmp.a<-array(dim=dim(a1)[c(2,3,1)]) for(i in 1:dim(a1)[1]) tmp.a[,,i]<-a1[i,,] a1<-tmp.a rm(tmp.a) Is it possible to avoid 'for' loop here? Thank you! --- Best regards, Wladimir mailto:wl at eimb.ru
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Wladimir Eremeev <wl at eimb.ru> writes:
Dear r-help, I have an array a1 with dimensions [1:660,1:65,1:25] I would like the first dimension to be the last one. That is I want and array [1:65,1:25,1:660] The only way to do this, I know, is tmp.a<-array(dim=dim(a1)[c(2,3,1)]) for(i in 1:dim(a1)[1]) tmp.a[,,i]<-a1[i,,] a1<-tmp.a rm(tmp.a) Is it possible to avoid 'for' loop here?
aperm() is your friend.
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 at biostat.ku.dk) FAX: (+45) 35327907
6 days later
Have you considered "aperm"? I found this listed under "See Also" for "?t". spencer graves
Wladimir Eremeev wrote:
Dear r-help, I have an array a1 with dimensions [1:660,1:65,1:25] I would like the first dimension to be the last one. That is I want and array [1:65,1:25,1:660] The only way to do this, I know, is tmp.a<-array(dim=dim(a1)[c(2,3,1)]) for(i in 1:dim(a1)[1]) tmp.a[,,i]<-a1[i,,] a1<-tmp.a rm(tmp.a) Is it possible to avoid 'for' loop here? Thank you! --- Best regards, Wladimir mailto:wl at eimb.ru
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