Re: MatrixForm affects values instead of only printing
- To: mathgroup at smc.vnet.net
- Subject: [mg100317] Re: [mg100298] MatrixForm affects values instead of only printing
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 1 Jun 2009 07:05:34 -0400 (EDT)
- Reply-to: hanlonr at cox.net
You included MatrixForm as part of the definition of test2
test2 = {-3, 7, 5} // MatrixForm
MatrixForm[{-3, 7, 5}]
?test2
Global`test2
test2=MatrixForm[{-3,7,5}]
You want MatrixForm applied to the output not the definition, i.e.,
(test2 = {-3, 7, 5}) // MatrixForm
MatrixForm[{-3, 7, 5}]
?test2
Global`test2
test2={-3,7,5}
test2[[3]]
5
Bob Hanlon
---- summer <summertan at hotmail.com> 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?