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Re: Re: two plots in Mathemtica 7. Bug?

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  • Subject: [mg95895] Re: [mg95759] Re: two plots in Mathemtica 7. Bug?
  • From: John Fultz <jfultz at>
  • Date: Thu, 29 Jan 2009 05:56:21 -0500 (EST)
  • Reply-to: jfultz at

On Mon, 26 Jan 2009 05:03:40 -0500 (EST), Bob F wrote:
> On Jan 25, 7:47 pm, "sv07171024" <steven_... at> wrote:
>> Hi,
>> when I execute
>> << ComputationalGeometry`;nodes = Table[Random[], {20}, {2}];
>> DiagramPlot[nodes] ; PlanarGraphPlot[nodes]
>> in Mathematica 7 I only get the latter (the Delaunay diagram), while,
>> IIRC, Mathematica 6 showed both. I found that I could get both plots if
>> I add a second semi-column between the plot statement. In this case
>> they are put side by side rather than above each other, with the
>> semi-columns between them.  A bug?
> A semicolon suppresses graphics output, just like it suppresses text
> output. So the behavior of the semicolon is now more consistent no
> matter what it refers to.
> I think this is true in version 6 and newer. But your comment about
> the two semicolons producing side by side plots completely stumps me.
> I tried it on my Mac with version 7 and it too gives side-by-side
> (though much smaller) plots of the two planar graphs.
> If you just put the first DiagramPlot[] command on its own line
> (without the semicolon) and you get both plots. e.g.
> << ComputationalGeometry`; nodes = Table[Random[], {20}, {2}];
> DiagramPlot[nodes]
> PlanarGraphPlot[nodes]
> -Bob

Concerning the mention of two semicolons...I thought somebody else might mention 
this, but if they did, I missed it.  A double semicolon is actually a completely 
different Mathematica operator.

In[1]:= FullForm[1;;2]
Out[1]//FullForm= Span[1,2]

So the plots are placed side-by-side with the doubled semicolon between them
because Mathematica is preserving it as a Span operator.

John Fultz
jfultz at
User Interface Group
Wolfram Research, Inc.

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