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Re: MatrixForm affects values instead of only printing

  • To: mathgroup at
  • Subject: [mg100368] Re: [mg100298] MatrixForm affects values instead of only printing
  • From: Murray Eisenberg <murray at>
  • Date: Tue, 2 Jun 2009 06:42:12 -0400 (EDT)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <>
  • Reply-to: murray at

Nothing wrong or inconsistent there. Look at:


Then, as expected:


And so the 3rd element of that is...


... which is the same result as from:

   test2[[1, 3]]

The MatrixForm is still lurking there, as you'll see if you evaluate:


Nothing has "changed"!

summer wrote:
> Here is the example:
> test1={-3, 7, 5}
> test1[[3]]
> returns the list and 5 as expected;
> test2={-3, 7, 5}//MatrixForm
> test2[[3]]
> returns a column vector and error: "part 3 of blah blah doesn't exist". The actual list itself is test2[[1]]. To get the right 3rd element I have to do:
> test2[[1,3]]
> which returns 5 as expected.
> The problem is MatrixForm is NOT supposed to change the expression it is applied on according to the manual. Is that a bug or there's logical explanation?

Murray Eisenberg                     murray at
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

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