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Groups > comp.soft-sys.math.mathematica > #1924
| From | "Scot T. Martin" <smartin@seas.harvard.edu> |
|---|---|
| Newsgroups | comp.soft-sys.math.mathematica |
| Subject | thoughts on how to explain this functionality? |
| Date | 2011-04-30 09:52 +0000 |
| Organization | Steven M. Christensen and Associates, Inc and MathTensor, Inc. |
| Message-ID | <ipgm48$8pt$1@smc.vnet.net> (permalink) |
In[1]:= x = 5
Out[1]= 5
In[2]:= With[{valueQ = If[ValueQ[ReleaseHold[Hold[#]]], #, False] &}, valueQ@x]
Out[2]= 5
In[3]:= With[{valueQ = If[ValueQ[#], #, False] &}, valueQ@x]
Out[3]= False
Anyone have thoughts on why Out[2] and Out[3] are different?
It seems to me that a ReleaseHold[Hold[...]] formulation would net out to no effect, yet the effect is apparent.
My desired output is Out[2] but the formulation of ReleaseHold[Hold[...]] is not elegant.
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thoughts on how to explain this functionality? "Scot T. Martin" <smartin@seas.harvard.edu> - 2011-04-30 09:52 +0000 Re: thoughts on how to explain this functionality? Stefan <wutchamacallit27@gmail.com> - 2011-05-01 10:21 +0000
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