Re: expression formatting inside tables
- To: mathgroup at smc.vnet.net
- Subject: [mg54682] Re: expression formatting inside tables
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Sun, 27 Feb 2005 01:29:06 -0500 (EST)
- Organization: The University of Western Australia
- References: <cvk3vk$d93$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <cvk3vk$d93$1 at smc.vnet.net>,
"David Park" <djmp at earthlink.net> wrote:
> Trevor,
>
> foo[x_] := x^2
>
> Table[{HoldForm[foo[j]], foo[j]} /. j -> i, {i, 5}] // TableForm
>
> If you look up the Table Help and then follow the link to Section A.4.2 on
> evaluation of iteration functions you will see why this is necessary. Table
> essentially creates a Block environment, sets i to an iterator value and
> then evaluates the argument. But HoldForm[foo[i]] does not evaluate so it
> does not get changed.
>
> However, you can substitute into held expressions using Rules.
I think a more elegant solution is
foo[x_] := x^2
p[i_] = {HoldForm[foo[i]], foo[i]}
Table[p[i], {i, 5}] // TableForm
Cheers,
Paul
--
Paul Abbott Phone: +61 8 6488 2734
School of Physics, M013 Fax: +61 8 6488 1014
The University of Western Australia (CRICOS Provider No 00126G)
35 Stirling Highway
Crawley WA 6009 mailto:paul at physics.uwa.edu.au
AUSTRALIA http://physics.uwa.edu.au/~paul