MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Part ([[...]]) and span (;;)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg84623] Re: Part ([[...]]) and span (;;)
  • From: Norbert Marxer <marxer at mec.li>
  • Date: Mon, 7 Jan 2008 02:40:45 -0500 (EST)
  • References: <flqcg3$k5e$1@smc.vnet.net>

On 6 Jan., 12:02, nigol <dario.butt... at gmail.com> wrote:
> In the Mathematica 6 help is written:
> =A0 =A0Common spans of parts include:
> =A0 =A0expr[[;;,j]] =A0 =A0 =A0 =A0 =A0 column j
> =A0 =A0If any of the Subscript[list, i] are All or ;;, all parts at that
> level are kept.
>
> On my platform the following works:
> In[1]:= {{a, b, c}, {d, e, f}, {g, h, i}}[[All, 2]]
> Out[1]= {b, e, h}
>
> but the following does not work:
> {{a, b, c}, {d, e, f}, {g, h, i}}[[;; , 2]]
> Syntax::sntxf: ";;" cannot be followed by ",2".
> Syntax::tsntxi: ",2" is incomplete; more input is needed.
> Syntax::sntxi: Incomplete expression; more input is needed.
>
> In[2]:= $Version
> Out[2]= "6.0 for Microsoft Windows (32-bit) (June 19, 2007)"
>
> Is this problem common to other platforms?
> Thanks,
> Dario

Hello

The documentation (at "More Information" for "Part") is not correct.

As cou can see under "Basic Examples" a few lines further down you
have to use (;;) instead of just ;;

i.e.   {{a, b, c}, {d, e, f}, {g, h, i}}[[(;;), 2]]

works as expected.

Best Regards
Norbert Marxer


  • Prev by Date: Re: parallel to a tabulated surface
  • Next by Date: Re: small init.m problem
  • Previous by thread: Part ([[...]]) and span (;;)
  • Next by thread: Re: Part ([[...]]) and span (;;)