Re: expression formatting inside tables
- To: mathgroup at smc.vnet.net
- Subject: [mg54613] Re: [mg54591] expression formatting inside tables
- From: "David Park" <djmp at earthlink.net>
- Date: Thu, 24 Feb 2005 03:21:16 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
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.
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: Trevor Baca [mailto:trevorbaca at gmail.com]
To: mathgroup at smc.vnet.net
hi mathgroup folks,
let
foo[x_] := x^2
then how to easily tableize the following?
foo[1] 1
foo[2] 4
foo[3] 9
foo[4] 16
foo[5] 25
because neither
Table[{HoldForm[foo[i]], foo[i]}, {i, 5}] // TableForm
nor
Table[{foo[HoldForm[i]], foo[i]}, {i, 5}] // TableForm
did what i was expecting.
trevor