Re: Generalizing Complement to handle multiple occurrences of elements
- To: mathgroup at smc.vnet.net
- Subject: [mg112456] Re: Generalizing Complement to handle multiple occurrences of elements
- From: Helen Read <hpr at together.net>
- Date: Thu, 16 Sep 2010 05:59:19 -0400 (EDT)
- References: <i6q0ml$l7c$1@smc.vnet.net>
- Reply-to: read at cems.uvm.edu
On 9/15/2010 4:38 AM, Mark Coleman wrote:
> Greetings,
>
> I'm wondering how one can efficiently generalize the built-in
> Complement function to return multiple occurrences of elements. For
> instance, the current version generates
>
> a={1,2,2,3,4,4,4,4}
> b={3,5,7}
>
> Complement[a,b]={1,2,4}
>
> I'm looking for a way to define
>
> myComplement[a,b]={1,2,2,4,4,4,4}
>
> My current code is very inefficient!
>
> Thanks,
>
> Mark
>
How about this:
Select[a, FreeQ[b, #] &]
--
Helen Read
University of Vermont