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MathGroup Archive 2005

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Re: Did something change?

  • To: mathgroup at
  • Subject: [mg58120] Re: [mg58109] Did something change?
  • From: Bob Hanlon <hanlonr at>
  • Date: Sun, 19 Jun 2005 03:43:23 -0400 (EDT)
  • Reply-to: hanlonr at
  • Sender: owner-wri-mathgroup at

    F[i]=ReplacePart[F[i], 7, {1,3}],{i,10}];


      ReplacePart[IdentityMatrix[8], 7, {1,3}],

Bob Hanlon

> From: Ronald Bruck <bruck at>
To: mathgroup at
> Date: 2005/06/18 Sat AM 06:08:27 EDT
> Subject: [mg58120] [mg58109] Did something change?
> Recently I created a list of several matrices, something like
>    Do[F[i] = IdentityMatrix[8]; F[i][[1,3]] = 7, {i,10}]
> and was surprised to get the message that F[i] wasn't a symbol.  I'm
> pretty sure code similar to that worked prior to Mathematica 5.  Did
> something change?
> I've also tried Symbolize[F[i]] in that loop, but it doesn't help;
> Mathematica refuses to access part [[1,3]] of F[i], claiming F[i] isn't
> a symbol.
> How are you supposed to set the individual values of a matrix if you
> can't do this?  This is an EXTREMELY unhelpful "feature".
> --Ron Bruck

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