[R] Trouble creating and adjacency matrix

[Daniel Malter]

x<-rnorm(25,1.5,1)
dim(x)=c(5,5)
x

y<-ifelse(c(x)>1.5,1,0)
dim(y)<-dim(x)

HTH,
Daniel


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
> 

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