[R] Function to find prime numbers

[Romain Francois]

On 10/13/2009 09:59 AM, AJ83 wrote:
>
>
> I need to create a function to find all the prime numbers in an array. Can
> anyone point me in the right direction?
> Thank you.
> AJ

There is isprime in package gmp.

 > data.frame( number = 1:10, is.prime = isprime( 1:10 ) > 1, 
is.probably.prime = isprime(1:10) > 0 )
    number is.prime is.probably.prime
1       1    FALSE             FALSE
2       2     TRUE              TRUE
3       3     TRUE              TRUE
4       4    FALSE             FALSE
5       5     TRUE              TRUE
6       6    FALSE             FALSE
7       7     TRUE              TRUE
8       8    FALSE             FALSE
9       9    FALSE             FALSE
10     10    FALSE             FALSE

See this: http://jostamon.blogspot.com/2009/02/goldbachs-comet.html for 
an example of its use.

Romain

-- 
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
|- http://tr.im/BcPw : celebrating R commit #50000
|- http://tr.im/ztCu : RGG #158:161: examples of package IDPmisc
`- http://tr.im/yw8E : New R package : sos