Thanks! That's what I need.

On Tue, Dec 29, 2009 at 1:33 PM, Dimitris Rizopoulos <
d.rizopoulos@erasmusmc.nl> wrote:

> have a look at ?ave(), e.g.,
>
> A <- 1:10
> B <- factor(c(1,2,2,4,4,4,7,7,7,7))
>
> ave(A, B)
>
>
> I hope it helps.
>
> Best,
> Dimitris
>
>
> faridamsb@gmail.com wrote:
>
>> Dear R experts,
>>
>> I would like to substitute the values of a vector, say A, with the average
>>  values taken over a factor
>>
>> For example, lets assume
>>
>>
>> A
>>
>> [1] 1 2 3 4 5 6 7 8 9 10
>>
>> B
>>
>> [1] 1 2 2 4 4 4 7 7 7 7
>> Levels: 1 2 4 7
>>
>> I need to have
>>
>> 1.0 2.5 2.5 5.0 5.0 5.0 8.5 8.5 8.5 8.5 8.5
>>
>> Thank you
>>
>>        [[alternative HTML version deleted]]
>>
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>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> --
> Dimitris Rizopoulos
> Assistant Professor
> Department of Biostatistics
> Erasmus University Medical Center
>
> Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
> Tel: +31/(0)10/7043478
> Fax: +31/(0)10/7043014
>

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