Re: [R] optimal way to compute matrix subtotals?
Thank you all for your replys! It is so much faster with rowsum(), thanks a million! Werner Dimitris Rizopoulos [EMAIL PROTECTED] schrieb: probably you want ?rowsum(); I hope it helps. Best, Dimitris Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm - Original Message - From: Werner Wernersen To: Sent: Friday, May 12, 2006 11:48 AM Subject: [R] optimal way to compute matrix subtotals? Hi! I have large matrices, one column per variable and I have a vector of factors / grouping symbols. Then I am computing subtotals for the groups but it takes pretty long and thus I wanted to ask if there is a better way to do it or if this is already the best way: subTotals - function(x, groupvec) do.call(rbind,lapply(split(x,groupvec),colSums,na.rm=T)) Thanks reading my question and any hints! Werner - [[alternative HTML version deleted]] __ 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 Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm - [[alternative HTML version deleted]] __ 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
[R] optimal way to compute matrix subtotals?
Hi! I have large matrices, one column per variable and I have a vector of factors / grouping symbols. Then I am computing subtotals for the groups but it takes pretty long and thus I wanted to ask if there is a better way to do it or if this is already the best way: subTotals - function(x, groupvec) do.call(rbind,lapply(split(x,groupvec),colSums,na.rm=T)) Thanks reading my question and any hints! Werner - [[alternative HTML version deleted]] __ 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
Re: [R] optimal way to compute matrix subtotals?
On Fri, 12 May 2006, Werner Wernersen wrote: Hi! I have large matrices, one column per variable and I have a vector of factors / grouping symbols. Then I am computing subtotals for the groups but it takes pretty long and thus I wanted to ask if there is a better way to do it or if this is already the best way: subTotals - function(x, groupvec) do.call(rbind,lapply(split(x,groupvec),colSums,na.rm=T)) I suggest you look at rowsum (on a transpose of your matrix). It will not handle NAs, though, if you have any. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ 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
Re: [R] optimal way to compute matrix subtotals?
Hi not sure about speed but aggregate can probably do it. aggregate(x, list(groupvec), sum, na.rm=T) HTH Petr On 12 May 2006 at 11:48, Werner Wernersen wrote: Date sent: Fri, 12 May 2006 11:48:45 +0200 (CEST) From: Werner Wernersen [EMAIL PROTECTED] To: r-help@stat.math.ethz.ch Subject:[R] optimal way to compute matrix subtotals? Hi! I have large matrices, one column per variable and I have a vector of factors / grouping symbols. Then I am computing subtotals for the groups but it takes pretty long and thus I wanted to ask if there is a better way to do it or if this is already the best way: subTotals - function(x, groupvec) do.call(rbind,lapply(split(x,groupvec),colSums,na.rm=T)) Thanks reading my question and any hints! Werner - [[alternative HTML version deleted]] __ 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 Petr Pikal [EMAIL PROTECTED] __ 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
Re: [R] optimal way to compute matrix subtotals?
probably you want ?rowsum(); I hope it helps. Best, Dimitris Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm - Original Message - From: Werner Wernersen [EMAIL PROTECTED] To: r-help@stat.math.ethz.ch Sent: Friday, May 12, 2006 11:48 AM Subject: [R] optimal way to compute matrix subtotals? Hi! I have large matrices, one column per variable and I have a vector of factors / grouping symbols. Then I am computing subtotals for the groups but it takes pretty long and thus I wanted to ask if there is a better way to do it or if this is already the best way: subTotals - function(x, groupvec) do.call(rbind,lapply(split(x,groupvec),colSums,na.rm=T)) Thanks reading my question and any hints! Werner - [[alternative HTML version deleted]] __ 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 Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm __ 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
