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Re: Row or column?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg112703] Re: Row or column?
  • From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
  • Date: Mon, 27 Sep 2010 05:48:42 -0400 (EDT)
  • References: <i7mq4c$ovt$1@smc.vnet.net>

Sam,

Mathematica considers the first level of a list as rows, the second,
nested, levels are the columns etc. So, for display purposes {{a, b}}
would show as a row, but if you want to use it for matrix/vector
multiplication you only need {a,b}, as Mathematica does not
differentiate between row or column vectors.

Cheers -- Sjoerd

On Sep 26, 8:44 am, Sam Takoy <sam.ta... at yahoo.com> wrote:
> Hi,
>
> How come
>
> {a, b} // MatrixForm
> {{a}, { b}} // MatrixForm
>
> produce identical outputs: columns?
>
> I would think that the first "matrix" is 1x2 and the second is 2x1.
>
> Alternatively, how do I produce a 1x2 matrix?
>
> Many thanks in advance,
>
> Sam



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