[R] extractor rows from a matrix

[billycorg]

Petr, it works!!!
thank you a lot!!!

Vincenzo


Petr Klasterecky wrote:
> 
> 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 <mailto:klaster at karlin.mff.cuni.cz>
>> /*Data:*/ 06/14/07 10:07:33
>> /*A:*/ billycorg <mailto:billycorg1 at virgilio.it>
>> /*Cc:*/ r-help at stat.math.ethz.ch <mailto:r-help at 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
>>  
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>>  
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>>  
>>  
>> 		
>> 
> 
> -- 
> Petr Klasterecky
> Dept. of Probability and Statistics
> Charles University in Prague
> Czech Republic
> 
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