Re: [R] extractor rows from a matrix Well, you cannot have a vector of vectors, you need a list of vectors.  With mean() and sum() it worked probably because these produce a single  number as their output. Also, the rbind() function won't help here, that  is for merging vector into a matrix. Once again, reading R-Intro is the  best advice I can give you. # creating an ampty list of length 1096: d <- list() length(d) <- 1096 # Filling the list with rows for(i in (1:1096)){ d[[i]] <- ht[i,] } Note the double bracketing when indexing lists: d[[1]] Please respond to the entire list next time, I only read these messages  occasionally. Petr vincenzo napsal(a): > thank you a lot for the answer >   > i don't expect one vector.. > but 1096 vector. >   > example: ht= >            1        2        3 > 1          3        4        5 > 2          4        5        8 > 3 > 4 > . > . > . > 1096  >   > i'd like 1096 vector like these: > d[1]= 3    4    5 > d[2]= 4    5    8 > ... >   > i'm trying now with this: > for(i in 1:1096) d[i]=(rbind(ht[i,]))  > but it doesn't work :( > it works with function like "mean","sum".. but not with "rbind" > what can i do? >   >   >   > /-------Messaggio originale-------/ >   > /*Da:*/ Petr Klasterecky  > /*Data:*/ 06/14/07 10:07:33 > /*A:*/ billycorg  > /*Cc:*/ r-help@stat.math.ethz.ch  > /*Oggetto:*/ Re: [R] extractor rows from a matrix >   > billycorg napsal(a): >  > thanks for the answer..but i don't find what i'm looking for! >  > >  > now i'm trying to expose better my problem: >  > i have: >  > >  > ht= a 1096rows x 3 columns matrix >  > >  > i'd like a function like this: >  > >  > d[i]=rbind(ht[i,]) for (i in 1:length(ht)) >  > >  > but this don't work :( >  > can anyone seriously help  me? >   > The problem is that people actually are trying to seriously help you, > but it is really difficult from your queries... >   > Please specify what you expect to be your output - a vector where you > just paste the rows of of the original matrix one by one? > If so, you can do > d <- t(ht) > dim(d) <- NULL >   > or (a 'dirty' way) > d <- c(t(ht)) >   > It is not at all clear what your statement should do. For example, what > is length(ht) with ht being a matrix? For R it is the total number of > elements, but did you mean this or the number of rows/columns?? >   > The suggestion to read R-Intro is the best advice you got here. >   > Petr >   > -- > Petr Klasterecky > Dept. of Probability and Statistics > Charles University in Prague > Czech Republic >   > __________ Informazione NOD32 2328 (20070613) __________ >   > Questo messaggio  Ã¨ stato controllato dal Sistema Antivirus NOD32 > http://www.nod32.it  >   >   > 		 >  --  Petr Klasterecky Dept. of Probability and Statistics Charles University in Prague Czech Republic ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.