[R] re stricting points in a data frame

Petr PIKAL petr.pikal at precheza.cz
Thu Jan 31 09:10:47 CET 2008


Maybe what is seeked is rather

between <- function (x,y) x>=range(y)[1] & x<=range(y)[2] 
A[between(A[,1], x1)& between(A[,2], x2),]

Regards

Petr
petr.pikal at precheza.cz

r-help-bounces at r-project.org napsal dne 30.01.2008 18:14:55:

> Let's A = expand.grid(xk1=xk1,xk2=xk2)
> 
> B = A[A[,1] %in% x1 & A[,2] %in% x2, ]
> 
> Should in principle produce the desired result.
> 
> Mama 
> 
> 
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> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of dxc13
> Sent: 30 January 2008 16:20
> To: r-help at r-project.org
> Subject: [R] re stricting points in a data frame
> 
> 
> useR's,
> 
> Consider some variables and a data frame of points:
> x1 <- c(1,2,3)
> x2 <- c(3,4,5)
> xk1 <- seq(min(x1)-.5, max(x1)+.5,.5)
> xk2 <- seq(min(x2)-.5, max(x2)+.5,.5)
> expand.grid(xk1=xk1,xk2=xk2)
> 
>    xk1 xk2
> 1  0.5 2.5
> 2  1.0 2.5
> 3  1.5 2.5
> 4  2.0 2.5
> 5  2.5 2.5
> 6  3.0 2.5
> 7  3.5 2.5
> ...
> 46 2.0 5.5
> 47 2.5 5.5
> 48 3.0 5.5
> 49 3.5 5.5
> 
> I want to restrict the data frame to only contain points that are within
> the
> x1 and x2 range.  So for this example, only points between 1 and 3
> should be
> kept for x1 and values between 3 and 5 should be kept for x2.  This
> condition needs to be satisfied for both points, not just one of them;
> i.e.,
> if an x1 point satisfies this, but its corresponding x2 point does not,
> then
> this point should be removed.
> Does anyone know a way to do this, in general, for any data frame? 
> Hope this is not confusing.
> Thanks in advance
> dxc13 
> -- 
> View this message in context:
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> 4381.html
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> 
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