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Re: DeleteCases and multiple patterns

• To: mathgroup at smc.vnet.net
• Subject: [mg93961] Re: DeleteCases and multiple patterns
• From: "m.g." <mg at michaelgamer.de>
• Date: Sun, 30 Nov 2008 06:57:12 -0500 (EST)
• References: <ggr217$e21$1@smc.vnet.net>

On 29 Nov., 10:29, guerom00 <guero... at gmail.com> wrote:
> Hello everyone :)
>
> I have, say a list of list. Each element is a list of length 3 i.e.
>
> myList={{x1,y1,z1},{x2,y2,z2},...{xN,yN,zN}}
>
> Now, let's say I want to delete from this list the element which have
> x=2 and 3 using DeleteCases.
> This works :
>
> DeleteCase[myList,{2,_,_}]
> DeleteCases[myList,{3,_,_}]
>
> but I would like to use
>
> DeleteCases[myList,{{2,_,_},{3,_,_}}]
>
> and this does not work...
>
> How do I combine multiple patterns in DeleteCases ?
>
> Thanks in advance.

Hello guero,

  I do not know how to realize this with "DeleteCases", but one
solution ist "the other way round" to select the elements you want
(and not to delete the ones you do not want): eg:

Select[myList,!((First[#] == 2 || First[#] == 3) &)]

this should work

Greetings

Mike