equating approximate values

Not sure what to make of the fact that your x, y are of different
lengths: if you mean to check all possible pairings, this is probably
what you need:

which(outer(x, y, "-") < threshold, arr.ind = TRUE)

Michael

On Sun, Dec 4, 2011 at 2:24 PM, andrija djurovic <djandrija at gmail.com> wrote:

Hi. Maybe this can help you (you can try additionally to incorporate
threshold):

set.seed(1)
x<-rnorm(10,10,1)
values <- sample(1:10,10) ?#values that we are looking for
mat <- matrix(c(x,values),ncol=2)

closest<-function(x,values) ? ?#function is an example from The R book

(Crawley)
+ {
+ x[which(abs(x-values)==min(abs(x-values)))]
+ }

apply(mat[,2,drop=FALSE],1,function(y) closest(mat[,1],y))

?[1] 10.183643 ?9.164371 ?9.164371 ?9.164371 ?9.164371 ?9.164371 ?9.164371
?9.164371
?[9] ?9.164371 ?9.164371


On Sun, Dec 4, 2011 at 7:00 PM, vamshi999 <vamshi999 at gmail.com> wrote:

Hello List,

I am having trouble finding the command for my problem.

I have two arrays x and y. now i would like to compare the values of x and
y
and then get the index of x which is exactly or approximately equal(+/-
some
value ) to the values in y.
?x <- runif(100,min=0,max=5)
?y <- runif(10,min=0,max=5)


the threshold value(+/-) value can vary. for this example lets take it to
be
.5

I know the regular method of doing this by writing different if and for
loops. But i have very big dataframe the computation time is very high for
this method. can anyone please tell me if there any functions to do this.

thank you for your help.

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