[R] enty-wise closest element

[Andreas Wittmann]

Thank you very much for your quick answers.

Sorry, but i forgot to explain i want to find the closest and smaller 
element for each entry, so ind1[3] is smaller as 11 and close to 11, 
ind1[2] is smaller as 5 and close to 5 and ind1[1] is smaller than 3 and 
close to 3.

best regards

Andreas




>
> On Jan 17, 2010, at 11:00 AM, Andreas Wittmann wrote:
>
>> Dear R-users,
>>
>> i have a simple problem maybe, but i don't see the solution. i want 
>> to find the entry-wise closest element of an vector compared with 
>> another.
>>
>> ind1<-c(1,4,10)
>> ind2<-c(3,5,11)
>>
>> for (i in length(ind2):1)
>> {
>> print(which.min(abs(ind1-ind2[i])))
>> }
>>
>> for ind2[3] it should be ind1[3] 10, for ind2[2] it should be ind1[2] 
>> 4 and for ind2[1] it should be ind1[1] 1. but with the for-loop above 
>> i get ind1[3], ind1[2] and ind1[2].
>>
>> any suggestions are quite welcome.
>
> You are failing to use the indices that which.min is providing. (And I 
> think the closest in ind1 to ind2[1] is not 1, but rather 4, so see if 
> this looks more responsive to your expectations:
>
> > for (i in length(ind2):1)
> + {
> + print( ind1[which.min(abs(ind1-ind2[i]))] )
> + }
> [1] 10
> [1] 4
> [1] 4
>>
>> best regards
>>
>> Andreas
>>
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>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>