[R] Select value according two vectors...

[Dieter Menne]

MarcioRibeiro wrote:
> 
> I have a problem in identifying a value between two vectors...
> Suppose vector A is...
> 0.0000 0.0909 0.0909 0.1818 0.2727 0.3636 0.4545 0.6363 0.0000 0.0000
> 0.0000 0.0000
> And vector B is...
> 3   5   7  18  43  85  91  98 100 130 230 487
> I would like to identify the value of vector B that vector A is bigger
> than 0.5, this means that I want to identify the 9-th value of vector B,
> that is 98.
> I know how to do that if I had the both vectors as a matrix, but I want to
> do this procedure with two vectors... 
> 
> 
Not much of a difference...

a=c(0.0000,0.0909,0.0909,0.1818,0.2727,0.3636,0.545,0.6363,
  0.0000,0.0000,0.0000,0.0000)
b= c(3,5,7,18,43,85,91,98,100,130,230,487)
b[min(which(a>0.5))] #but fails ungraciously if there is no solution

# better use a dataframe or matrix and sort
set.seed(4711)
ab = data.frame(a=rnorm(10),b=rnorm(10))
ab = ab[order(ab$a),]
ab$b[min(which(ab$a>0.5))] # ok, not very nice if there is no solution

Dieter

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