[R] How to doulbe all the value on a matrix

[David Winsemius]

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On Jan 17, 2011, at 4:38 PM, André Dias wrote:

> OK!!
>
> So, the ideia is from the 1st matrix get the 2nd matrix with the use  
> of a vector.
>
> is it possible?


Peter B already gave you an answer.

 > m[c(2,7, 8), c(1,4,6, 7)]
      V1 V4 V6 V7
[1,]  7  3 16  9
[2,]  3  2  9 18
[3,] 13 16  8  9


>
> In the example I have a 10x10 matrix and I get from that one a  
> second 4x3 matrix selected from a vector.

Then you should have presented the logical conditions for selecting  
that matrix rather than expecting us to guess what they might be.  
Please (re?)read the Posting Guide about what is expected of  
questioners regarding presenting complete examples of data and code.

-- 
David.

>
> thanks
> ADias
>
>
> 2011/1/17 David Winsemius <dwinsemius at comcast.net>
>
> On Jan 17, 2011, at 11:16 AM, ADias wrote:
>
>
> Hi,
>
> yes it works perfectly.
>
> I have another question:
>
> Is there way of selecting with a vector the values I wish to take  
> out from a
> matrix.
>
> Example:
>
> I have this matrix and I want to take out the numbers in bold and  
> get the
> second matrix below
>
> This is a plain text mailing list (despite what the Nabble mirror  
> may (mis-)lead you into believing) ... no bold.
>
> -- 
> david.
>
> m
>     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> [1,]   17    1    6    5   19    2   19    1   15     8
> [2,]    7    7   20    3    2   16    9    9   19    13
> [3,]    2    4    3   11   18   11   14   13    3     1
> [4,]    3    7    5    7   17   18   10    6    5    15
> [5,]    8   20   13   10    8   12   20   19    1    16
> [6,]    9   14    1   12   12   12   17   18   10    17
> [7,]    3   10   11    2   12    9   18    6   19     9
> [8,]   13    2   17   16   18    8    9   14    9    16
> [9,]    9    4   11    4    1   17    9    7   20    12
> [10,]    9    1    4    8    8   19   19    8   17    18
>
>    [,1] [,2] [,3] [,4]
> [1,]    7    3   16    9
> [2,]    3    2    9   18
> [3,]   13   16    8    9
>
> thanks
> AD
>
> -- 
> View this message in context: http://r.789695.n4.nabble.com/How-to-doulbe-all-the-value-on-a-matrix-tp3221213p3221230.html
>
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>
> David Winsemius, MD
> West Hartford, CT
>
>

David Winsemius, MD
West Hartford, CT