RE: Problem with HoldForm & Unevaluated
- To: mathgroup at smc.vnet.net
- Subject: [mg94495] RE: [mg94468] Problem with HoldForm & Unevaluated
- From: "David Park" <djmpark at comcast.net>
- Date: Mon, 15 Dec 2008 07:42:30 -0500 (EST)
- References: <29509549.1229261132483.JavaMail.root@m02>
Syd,
You could give an Attribute to printf.
ClearAll[printf];
Attributes[printf] = HoldFirst;
printf[fn_] := Print[HoldForm[fn], " = ", fn]
printf[Rationalize /@ {-1.7, 1.39646, -0.37188}]
SequenceForm[
HoldForm[
Map[Rationalize, {-1.7, 1.39646, -0.37188}]], " = ", {
Rational[-17, 10],
Rational[69823, 50000],
Rational[-9297, 25000]}]
Or, since you have Presentations, you could use:
Needs["Presentations`Master`"]
command[Rationalize /@ {-1.7, 1.39646, -0.37188}]
and the result appears with a tooltip that displays the input statement.
David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/
From: Syd Geraghty [mailto:sydgeraghty at me.com]
Hi all,
A seemingly simple function has me baffled and I would appreciate a
solution.
I am trying to define a personal print function that prints
"Unevaluated function string" = Evaluated function!
I have tried many examples in guide/EvaluationControl documentation
without getting what I want.
A simple example;
printf[fn_] := Print[HoldForm[fn], " = ", fn];
printf[Rationalize /@ {-1.7, 1.39646, -0.37188}]
Print[HoldForm[Rationalize /@ {-1.7, 1.39646, -0.37188}], " = ",
Rationalize /@ {-1.7, 1.39646, -0.37188}]
gives the LHS evaluated:
{-(17/10),69823/50000,-(9297/25000)} = {-(17/10),69823/50000,-
(9297/25000)}
Instead of the hoped for output:
Rationalize/@{-1.7,1.39646,-0.37188} = {-(17/10),69823/50000,-
(9297/25000)}
Using Unevaluated seemed to me should fix it but does not.
Thanks in advance for your help.
Cheers ... Syd
PS I've tried Mathematica 5.2 as well as 7.0
Syd Geraghty B.Sc, M.Sc.
sydgeraghty at mac.com
Mathematica 7.0.0 for Mac OS X x86 (64 - bit) (21st November, 2008)
MacOS X V 10.5.4
MacBook Pro 2.33 Ghz Intel Core 2 Duo 2GB RAM