Re: A list of numbers without "73"
- To: mathgroup at smc.vnet.net
- Subject: [mg63006] Re: A list of numbers without "73"
- From: "Thomas Schmelzer" <thomas.??? at balliol.ox.ac.uk>
- Date: Sun, 11 Dec 2005 04:56:29 -0500 (EST)
- Organization: Balliol College
- References: <dnee1r$1ep$1@smc.vnet.net>
- Reply-to: "Thomas Schmelzer" <thomas.??? at balliol.ox.ac.uk>
- Sender: owner-wri-mathgroup at wolfram.com
I forgot to say that S(i) is a list of positive integers with i digits. Best, Thomas "Thomas Schmelzer" <thomas.??? at balliol.ox.ac.uk> schrieb im Newsbeitrag news:dnee1r$1ep$1 at smc.vnet.net... > Experts, > > S(i) should be a list of positive integers without the substring "73". > > My code seems to be very inefficient. I multiply all numbers with 0 if > they > contain "73", sort the new list, make the union (remove double elements) > and > delete the first element. Therefore it is necessary to use an if statement > in order not to delete the first element of the numbers 1-9. Any more > sophisticated ideas? > > L := Table[k, {k, 1, 9}] > > S[i_] := S[i] = > If[i == 1, L, > Delete[Union[ > Table[k*(1 - Boole[StringMatchQ[ToString[k], "*73*"]]), {k, > 10^(i - 1), 10^i - 1}]], 1]] > > > > Best > > Thomas