yes you are right .... it was my inattention it is friday and my head needs
to start the week end  sorry;-)

2012/6/8 David Winsemius <dwinsemius@comcast.net>

>
> On Jun 8, 2012, at 12:33 PM, Guido Leoni wrote:
>
>  Dear list
>> Is there a way  to extract a random sample without duplicated row from a
>> dataframe ?.
>> a=c(1,2,3,1,1,1,2,1)
>> b=c(1,2,3,1,2,1,2,1)
>> c=c(1,1,1,1,1,1,1,1)
>> d=c(1,2,3,1,1,1,2,1)
>> prov<-data.frame(a,b,c,d)
>> prov2<-prov[sample(1:nrow(**prov),5,replace=T),]
>> prov2
>>   a b c d
>> 3   3 3 1 3
>> 6   1 1 1 1
>> 3.1 3 3 1 3
>> 5   1 2 1 1
>> 8   1 1 1 1
>>
>> I tryed  the above code but as you can see sample function includes also
>> duplicates.
>> thank you for any tip
>>
>
> Why would you use replace=T if you didn't want duplicates???
>
> --
>
> David Winsemius, MD
> West Hartford, CT
>
>


-- 
Guido Leoni
National Research Institute on Food and Nutrition
(I.N.R.A.N.)
via Ardeatina 546
00178 Rome
Italy

tel     + 39 06 51 49 41 (operator)
        + 39 06 51 49 4498 (direct)

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