[R] equating approximate values

[R. Michael Weylandt]

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.
>>
>> --
>> View this message in context:
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>> Sent from the R help mailing list archive at Nabble.com.
>>
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