Bill Dunlap sent me a couple of more compact versions and perhaps
forgot the hit "reply all":
Data[ Data[,1]^2 + Data[,2]^2 >= 49, , drop=FALSE]
And a second one that handles higher dimensions than 2, still with and
L2 metric:
Data[ rowSums(Data^2)>49, , drop=FALSE]
--
David Winsemius
On Nov 23, 2009, at 6:13 PM, David Winsemius wrote:
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
--
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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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
______________________________________________
R-help@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.
