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Re: Display/manipulating numeric values inside a DynamicModule[]

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110770] Re: Display/manipulating numeric values inside a DynamicModule[]
  • From: Helen Read <hpr at together.net>
  • Date: Mon, 5 Jul 2010 06:03:56 -0400 (EDT)
  • References: <i0pc54$ju6$1@smc.vnet.net>
  • Reply-to: HPR <read at math.uvm.edu>

On 7/4/2010 3:10 AM, Leo Alekseyev wrote:
> Recently, I've been using DynamicModules[] to interactively explore
> some plots that I make -- by introducing a locator, whose coordinates
> allow me to trace the plotted data in some fashion (e.g. by displaying
> the function value for the x coordinate of the locator, or finding the
> closest plotted point to a locator in a ListPlot, etc.)  My problem is
> that I haven't figured out a good way to display dynamically updated
> values as part of the plot or, for that matter, perform manipulations
> with the dynamic values.  The reason seems to be that once an
> expression has head Dynamic, the behavior of many familiar functions
> changes (e.g. NumericQ on a dynamic value returns False, which makes
> it impossible to numerically evaluate Re or Im, etc.)  Below is a
> simple example of what I'm doing, and workaround that I came up with.
> Here are some concrete questions:
>
> (a) is there a better way to display the dynamic values "a" and "b"
> inside a formatted string?..  My workaround is to use something like
> Grid[{{"a:", a, "; b:", b}}], which is not entirely satisfactory

I use Row for that sort of thing, and use Style to format it however you 
like. You can style individual elements or the entire row.

Row[{Style["a: ", Blue, Bold], Style[a, Bold], Style["\nb: ", Red],
   Style[b, 14, Italic]}]


Style[Row[{"a: ", a, "\nb: ", b}], 16, Red, Bold]


You can stick the Row right in a PlotLabel if you like.

PlotLabel -> Style[Row[{"a: ", a, "\nb: ", b}], 16, Red, Bold]



I don't have good answers for your questions (b) and (c) and will defer 
to others.


-- 
Helen Read
University of Vermont


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