Re: SsssComplement?
- To: mathgroup at smc.vnet.net
- Subject: [mg37866] Re: SsssComplement?
- From: Erich Mueller <emueller at mps.ohio-state.edu>
- Date: Fri, 15 Nov 2002 01:36:35 -0500 (EST)
- Organization: Ohio State University
- References: <ar00gn$b6h$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
The following function is pretty fast:
UnsortedComplement2[x_List, y__List] :=
Module[{f}, f[a_] = a; (f[#] = Sequence[]) & /@ Join[y]; f /@ x]
Erich
On Thu, 14 Nov 2002, Mozalev Vasil wrote:
> Hi. Excuse me for poor-quality English language.
> My question about "Complement" and "UnsortedComplement".
> Function " UnsortedComplement [list, listi] " working more slowly then
> function " Complement
> [list, listi] " because deletes elements "listi" behind many passes, whereas
> " Complement [list,
> listi] " it makes for one pass.
> What kind of procedure I can use to write " SssssComplement [list, list1] "
> for maintenance of
> removal elements "list1" from "list" without sorting, but for one pass?
> The specified lists already are sorted before their processing by function "
> SssssComplement
> [list, list1] ".
> It is necessary for acceleration of accounts.
> Example for check of correctness of work of required function:
> SssssComplement [{1,3,5,7,10}, {3, 7,10}] should give
> {1,5}.
> But
> SssssComplement [{1,3,5,7,10}, {7,3,10}] should give
> {1,3,5}, as for one pass the number 3 will not leave.
> Thank you.
> Vasil.
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