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Re: Help with Delete cases

• To: mathgroup at smc.vnet.net
• Subject: [mg116252] Re: Help with Delete cases
• From: Bill Rowe <readnews at sbcglobal.net>
• Date: Tue, 8 Feb 2011 05:07:25 -0500 (EST)

On 2/7/11 at 6:06 AM, ramsey2879 at msn.com (KenR) wrote:

>I have a list= Range[3003]  I want to delete cases of n = m(m+1) mod
>P from the list, but Delete cases only deletes cases matching a
>pattern, i.e.

>list = DeleteCases[list,Mod[N - m(m+1)/2,P] = 0] will definitely not
>work.  I want to keep list, as the same identifier, throughout since
>this is within a looping process. Any suggestions?

Change the code to be something like:

list = DeleteCases[list,_?(Mod[#(#+1)/2,P] == #&)]

That is use a pure function to set up a test that is true for
the things you want to delete.