[R] A matrix calculation
David Winsemius
dwinsemius at comcast.net
Sun Aug 23 21:08:02 CEST 2009
On Aug 23, 2009, at 2:53 PM, Bogaso wrote:
>
> No no, I actually want following result :
>
> 7, 14, 21, 6, 13, 20, 5, 12, 19,............
Ooops. That is what I thought you wanted, but I didn't check very
carefully, did I?
c(apply(mat[7:1,],1,I) )
# the I() function just returns "itself" and gets supplied a row at a
time.
[1] 7 14 21 6 13 20 5 12 19 4 11 18 3 10 17 2 9 16 1 8 15
>
>
>
>
>
> David Winsemius wrote:
>>
>>
>> On Aug 23, 2009, at 2:37 PM, Bogaso wrote:
>>
>>>
>>> I have suppose a matrix like that
>>>
>>>> mat <- matrix(1:21, 7)
>>>> mat
>>> [,1] [,2] [,3]
>>> [1,] 1 8 15
>>> [2,] 2 9 16
>>> [3,] 3 10 17
>>> [4,] 4 11 18
>>> [5,] 5 12 19
>>> [6,] 6 13 20
>>> [7,] 7 14 21
>>>
>>>> From this matrix, I want to create a vector like tha :
>>>
>>> c(mat[7,], mat[6,], mat[5,], ....., mat[1,])
>>>
>>> Can anyone please guide me, how to do that?
>>
>> c( mat[7:1,] )
>>
>> # [1] 7 6 5 4 3 2 1 14 13 12 11 10 9 8 21 20 19 18 17 16 15
>>
>> --
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>> ______________________________________________
>> R-help at 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.
>>
>>
>
> --
> View this message in context: http://www.nabble.com/A-matrix-calculation-tp25106048p25106224.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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