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Re: pattern matching and droping elements from list of lists.

• To: mathgroup at smc.vnet.net
• Subject: [mg49759] Re: [mg49742] pattern matching and droping elements from list of lists.
• From: Ken Levasseur <klevasseur at mac.com>
• Date: Fri, 30 Jul 2004 06:02:11 -0400 (EDT)
• References: <200407291146.HAA10396@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Sean:

Try this:

Outer[List, {a,b,c}, {a,b,c}, {a,b,c}]]]//
      Flatten[#, 2] &//
      Select[#, Not[SameQ @@ #]& ] &

{{a, a, b}, {a, a, c}, {a, b, a}, {a, b, b}, {a, b, c},
   {a, c, a}, {a, c, b}, {a, c, c}, {b, a, a}, {b, a, b},
   {b, a, c}, {b, b, a}, {b, b, c}, {b, c, a}, {b, c, b},
   {b, c, c}, {c, a, a}, {c, a, b}, {c, a, c}, {c, b, a},
   {c, b, b}, {c, b, c}, {c, c, a}, {c, c, b}}

Ken Levasseur
Math. Sci.
UMass Lowell


On Jul 29, 2004, at 7:46 AM, sean kim wrote:

> hello group,
>
> Outer[List, {a, b, c}, {a, b, c}, {a, b, c}]
>
> will output
>
> {{
> {{a, a, a}, {a, a, b}, {a, a, c}}, {{a, b, a}, {a, b, b}, {a, b, c}},
> {{a, c, a}, {a, c, b}, {a, c, c}}},
> {{{b, a, a}, {b, a, b}, {b, a, c}}, {{b, b, a}, {b, b, b}, {b, b, c}},
> {{b, c, a}, {b, c, b}, {b, c, c}}},
> {{{c, a, a}, {c, a, b}, {c, a, c}}, {{c, b, a}, {c, b, b}, {c, b, c}},
> {{c, c, a}, {c, c, b}, {c, c, c}}
> }}
>
> how do I remove {a,a,a} and {b,b,b} and {c,c,c} from above?
>
> thanks all in advance for any insights
>
> sean
>

• References:
  • pattern matching and droping elements from list of lists.
    • From: sean_incali@yahoo.com (sean kim)