Hi Léa,

Try

ifelse(DistanceMatrix > 1.5, 0, 1)

HTH,
Jorge


On Sun, Sep 25, 2011 at 5:07 PM, Spartina <> wrote:

> Hello all,
>
> I'm having trouble creating an adjacency matrix.
>
> Basically, I need to turn the following distance matrix into an adjacency
> matrix based on whether values are >1.5 or not. If they are >1.5, then the
> returned value should be 0. If they are =<1.5, then the returned value
> should be 1.
>
> DistanceMatrix:
>
>           A             B          C             D          E
> [1,] 0.000000 2.828427 1.581139 2.236068 2.000000
> [2,] 2.828427 0.000000 1.581139 4.123106 2.000000
> [3,] 1.581139 1.581139 0.000000 2.549510 2.121320
> [4,] 2.236068 4.123106 2.549510 0.000000 4.123106
> [5,] 2.000000 2.000000 2.121320 4.123106 0.000000
>
> I'm trying to do this via the if statement, however I can't get it to work
> and it keeps returning an error message:
>
> > if(DistanceMatrix>1.5) {0} else {1}
> [1] 1
> Warning message:
> In if (DistanceMatrix > 1.5) { :
> the condition has length > 1 and only the first element will be used
>
>
> I am brand new to R and have a very limited knowledge of functions and
> syntax. Maybe the if statement is not even the right way of tackling this
> problem....
>
> Thanks in advance for your answers!
>
> Léa
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Trouble-creating-and-adjacency-matrix-tp3842106p3842106.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.
>

	[[alternative HTML version deleted]]

