Re: With[{software=Mathematica}, Frustration]

*To*: mathgroup at smc.vnet.net*Subject*: [mg24385] Re: [mg24308] With[{software=Mathematica}, Frustration]*From*: AES <siegman at stanford.edu>*Date*: Wed, 12 Jul 2000 23:13:25 -0400 (EDT)*Organization*: Stanford University*References*: <vfca5.325$f6.112205@ralph.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <vfca5.325$f6.112205 at ralph.vnet.net>, Wolf Hartmut <hwolf at debis.com> wrote: > In[2]:= With[{a = 2, b = 3}, Evaluate[c]] > Out[2]= 6 > > will do what you want! Why? What was meant saying by the quotations > is that With gives a *textual* substitution for the given variables > occuring in the *unevaluated* body. Thanks for this reply, and others. But, there is still frustration. What I really want is as follows. I'm entering a bunch of functional relations like c = a b, using direct assignments (=, not :=) and being careful not to give values to the independent variables like a and b as I go along At various points I'd like to print out numerical test values or check values of these functions, like for example With[ {a=2, b=3}, Print["a = ",a,", b = ",", c =",c,", Sin[c] = ",Sin[c] ] ] just to check what some typical values might be, or to check that the results are reasonable. Challenges: 1) Try wrapping the "Print" statement, or the "c" value, or the "Sin[c]", or various combinations of these, within Evaluate[]'s -- **and then try predicting in advance, based on your knowledge of Mathematica, what these different combinations will do**. 2) Find *any* combination of With, Print and Evaluate that will accomplish the elementary "print a trial result" task that's wanted above. (I haven't found one yet.). 3) Finally, reconsider your explanation of *textual* substitution. With[ ] will "textually substitute" within the Evaluated form of c -- but not in the "a =" strings -- which are expressions -- and hence should be "variables" in a sense.. Try, for example With[{a=2}, Evaluate[{"a = ",a}] What gets "textually substituted"? -- what's Mathematica "code"? (see the Book) -- in this case, and what isn't?