[R] Re moving rows which do not satisfy a condition

[David Winsemius]

On Nov 23, 2009, at 2:57 PM, sandsky wrote:

>
> Hello,
>
> Considering 5 points in X-Y plain. Data is a 5*2 matrix (5 rows for  
> samples
> & 2 columns for X and Y)
> With a distance from the origin, if a distance < 7, remove the row  
> from the
> Data.
>
> After calculating the distance for each point, I can't forward  
> because of
> this "Removing" problem.
>
> Anyone can help me?
>
>
> Data=matrix(1:10,5,2)

 > Data[apply(Data, 1, function(x) sqrt(x[1]^2+x[2]^2)>=7), ]
      [,1] [,2]
[1,]    2    7
[2,]    3    8
[3,]    4    9
[4,]    5   10

>
> a=rep(0,5);
> b=rep(0,5);
>
> for (i in 1:5))
>  {
>     for (k in 1:2)
>     {	
>        a[i,k]=a[i,k]+(Data[i,k])^2
>     }
>     b[i,j]=(a[i,j])^0.5   # distance from the origin
>  }	
>
>
> Thank you,
>
> Jin
> 	
>
>
> -- 
> View this message in context: http://old.nabble.com/Removing-rows-which-do-not-satisfy-a-condition-tp26484778p26484778.html
> Sent from the R help mailing list archive at Nabble.com.
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT