MathGroup Archive 1996

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

Search the Archive

Re: iterator strings as lists?

  • To: mathgroup at
  • Subject: [mg3528] Re: iterator strings as lists?
  • From: wagner at bullwinkle.cs.Colorado.EDU (Dave Wagner)
  • Date: Wed, 20 Mar 1996 02:51:32 -0500
  • Organization: University of Colorado, Boulder
  • Sender: owner-wri-mathgroup at

In article <4ifhl5$518 at>,
J.P. and/or Valerie Purswell <purswell at> wrote:
>In this example, listlimits1a is a list containing 3 elements, and Mma 
>does not accept  it as the second arguement in Table[].  When the string {i, 
>1,5} is just typed normally, the command executes as expected
>listlimits1a = {i, 1, 5}
>>{i, 1, 5}
>Table[i, listlimits1a]
>   Argument listlimits1a at position 2
>     does not have the 
>>correct form for an iterator.Table[i, listlimits1a]

This happens because Table has the HoldAll attribute.  The first
argument to Table must not be allowed to evaluate before the values
for the iteration variable can be substituted.

The workaround is to use Table[i, Evaluate[listlimits1a]].

>the difference between being able to substutite an expression for the second 
>arguement in Table and Take seems to be related to the fact that the Table[] 
>command is an iterator.  Is there some (deliberate)  reason for mathematica to 
>not accept an expression for the second argument, or was it simply not coded 
>that way?  If the answer is (b) is there some work-around?  

I don't know what the design rationale for this is.  It seems to
me like Table could get by with the HoldFirst attribute, but maybe
there's some pathological case of which we're not aware that precludes

		Dave Wagner
		Principia Consulting
		(303) 786-8371
		dbwagner at


  • Prev by Date: Re: Generating inverse functions
  • Next by Date: Combining ListPlotVectorField and ListDensityPlot
  • Previous by thread: problems with mathematica on solaris box
  • Next by thread: Re: iterator strings as lists?