[R] Finding cases in one subset that are closet to another subset

[David Winsemius]

On Dec 2, 2009, at 3:01 PM, Peter Flom wrote:

> Good afternoon
>
> Running R2.10.0 on Windows
>
> I have a data frame that includes (among much else) a factor  
> (In_2006) and a continuous variable (math_3_4).  I would like to  
> find the 2 cases for In_2006 = 0 that are closest to each case where  
> In_2006 = 1.
>

You ask for closest which would imply a singleton, but you also ask  
for cases (plural). Define "closest", please.

> My data looks like
>
>     In_2006 math_3_4
>         0     55.1
>         1     51.6
>         1     18.1
>         1     26.6
>         1     14.1
>         1      9.6
>         1     48.9
>         1     12.9
>         0     63.0
>         0     51.8
>
> etc. for several hundred rows.
>
> I would like a new data frame that has all the cases where In_2006 =  
> 1, and those cases of In_2006 that are closest to those cases
>
> Thanks in advance
>
> Peter
>
> Peter L. Flom, PhD
> Statistical Consultant
> Website: www DOT peterflomconsulting DOT com
> Writing; http://www.associatedcontent.com/user/582880/peter_flom.html
> Twitter:   @peterflom
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT