[R] help: selection of data

stephen sefick ssefick at gmail.com
Sat Oct 25 19:19:45 CEST 2008


#is this what you want?
x <- c(-10, -5, 0, 5, 10, 15, 20)
y <- c(10, 10, 10, -5, -6, -7, 10)
data <- data.frame(x, y)
subset(data, x>0 & y==min(y))

On Sat, Oct 25, 2008 at 12:33 PM, Martin Ballaschk <qcumba at web.de> wrote:
> Hi,
>
> I'm not very experienced with R and struggle with data selection from a long
> matrix with two columns.
>
> I want to cut out the data between x > 0 and min(y).
>
>> x <- c(-10, -5, 0, 5, 10, 15, 20)
>> y <- c(10, 10, 10, -5, -6, -7, 10)
>> data <- as.matrix( cbind(x, y) )
>
>> data
>       x  y
> [1,] -10 10
> [2,]  -5 10
> [3,]   0 10 _
> [4,]   5 -5  |-- data interval
> [5,]  10 -6 _|   to be selected
> [6,]  15 -7
> [7,]  20 10
>
>
> I need that to select the interval between a time 0 and a peak that is the
> minimum here to fit that interval via nls() later.
>
> Can anybody help? I would be very thankful for general hints how to select
> data with the help of conditions.
>
> Cheers
> Martin
>
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>



-- 
Stephen Sefick
Research Scientist
Southeastern Natural Sciences Academy

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

								-K. Mullis



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