[R] Create blocks or observations

[David Winsemius]

On Mar 25, 2010, at 9:21 PM, tj wrote:

>
> Anyone who can help me with this?
> I have 48 observations (I dont want to alter their order). I want to  
> group
> these observations into 16 blocks. So I should have 3 observations  
> for each
> block. This is what I did in R, but it has warnings.
>
>> y                 #contains my 48 observations
> [1] 2.4 2.4 2.4 2.2 2.1 1.5 2.3 2.3 2.5 2.0 1.9 1.7 2.2 1.8 3.2 3.2  
> 2.7 2.2
> 2.2
> [20] 1.9 1.9 1.8 2.7 3.0 2.3 2.0 2.0 2.9 2.9 2.7 2.7 2.3 2.6 2.4 1.8  
> 1.7 1.5
> 1.4
> [39] 2.1 3.3 3.5 3.5 3.1 2.6 2.1 3.4 3.0 2.9

Consider:

 > ygrp <- matrix(y, ncol=3, byrow=TRUE)
 > ygrp
       [,1] [,2] [,3]
  [1,]  2.4  2.4  2.4
  [2,]  2.2  2.1  1.5
  [3,]  2.3  2.3  2.5
  [4,]  2.0  1.9  1.7
  [5,]  2.2  1.8  3.2
  [6,]  3.2  2.7  2.2
  [7,]  2.2  1.9  1.9
  [8,]  1.8  2.7  3.0
  [9,]  2.3  2.0  2.0
[10,]  2.9  2.9  2.7
[11,]  2.7  2.3  2.6
[12,]  2.4  1.8  1.7
[13,]  1.5  1.4  2.1
[14,]  3.3  3.5  3.5
[15,]  3.1  2.6  2.1
[16,]  3.4  3.0  2.9

 > ygrp[16, ]
[1] 3.4 3.0 2.9

-- 
David.

>> g=c(0,0,0)         #storage vector
>> for (i in 1:16){
> + g[i]=y[(3*i-2) : (3*i)]
> + }
> There were 16 warnings (use warnings() to see them)
>> g[1]
> [1] 2.4
>> g[2]
> [1] 2.2
>>
>
> ###### g[1] should show 2.4 2.4 2.4
> ###### g[2] should show 2.2 2.1 1.5
> ######g[16] should show 3.4 3.0 2.9
>
> Can you please tell me how I should correct my program?
> Thank you.
>
> ~tj
>
> -- 
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