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Re: HoldForm

  • To: mathgroup at smc.vnet.net
  • Subject: [mg68099] Re: HoldForm
  • From: "J Siehler" <jsiehler at gmail.com>
  • Date: Mon, 24 Jul 2006 00:55:41 -0400 (EDT)
  • References: <e9v992$gjr$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

> This code displays the component differences of matrix subtraction (A-B):
> A = {{1, 2}, {3, 4}};
> B = {{5, 6}, {7, -8}};
> Map[MapThread[HoldForm[#1 - #2] &, {A[[#]], B[[#]]}] &, Range@2]
> As desired, the output is {{1 - 5, 2 - 6}, {3 - 7, 4--8}}.
> Two questions:
> - What's a better way to do this?
> - How can I replace the -- by +?

A={{1,2},{3,4}};
B={{5,6},{7,-8}};

inertPlus[l___]:=HoldForm[Plus[l]]
SetAttributes[inertPlus,Listable]

inertPlus[A,-B]

{{1-5,2-6},{3-7,4+8}}


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