[R] how to select an element from a vector based on a probability

[Simone Gabbriellini]

Hello, Rui,

it does, indeed!

thanks,
Simone

2014-04-10 20:55 GMT+02:00 Rui Barradas <ruipbarradas at sapo.pt>:
> Hello,
>
> Use ?sample.
>
> sample(x, 1, prob = x)
>
> Hope this helps,
>
> Rui Barradas
>
> Em 10-04-2014 19:49, Simone Gabbriellini escreveu:
>
>> Hello List,
>>
>> I have an array like:
>>
>> c(4, 3, 5, 4, 2, 2, 2, 4, 2, 6, 6, 7, 5, 5, 5, 10, 10, 11, 10,
>> 12, 10, 11, 9, 12, 10, 36, 35, 36, 36, 36, 35, 35, 36, 37, 35,
>> 35, 38, 35, 38, 36, 37, 36, 36, 37, 36, 35, 35, 36, 36, 35, 35,
>> 36, 35, 38, 35, 35, 35, 36, 35, 35, 35, 6, 5, 8, 6, 6, 7, 1,
>> 7, 7, 8, 9, 7, 8, 7, 7, 13, 13, 13, 14, 13, 13, 13, 14, 14, 15,
>> 15, 14, 13, 14, 39, 39, 39, 39, 39, 39, 41, 40, 39, 39, 39, 39,
>> 40, 39, 39, 41, 41, 40, 39, 40, 41, 40, 41, 40, 40, 40, 39, 41,
>> 39, 39, 39, 39, 40, 39, 39, 40, 40, 39, 39, 39, 1, 4, 3, 4)
>>
>> I would like to pick up an element with a probability proportional to
>> the element value, thus higher values should be picked up more often
>> than small values (i.e., picking up 38 should be more probable than
>> picking up 3)
>>
>> Do you have any idea on how to code such a rich-get-richer mechanism?
>>
>> Best regards,
>> Simone
>>
>



-- 
-----------------------------------------------------------------

Simone Gabbriellini, PhD

Post-doctoral Researcher
ANR founded research project "DIFFCERAM"
GEMASS, CNRS & Paris-Sorbonne.

mobile: +39 340 39 75 626
email: simone.gabbriellini at cnrs.fr