Get all the symbols with a pattern and save their Own, Down & Up values?

Questions
1

Example question: I look for all the symbols with a pattern: foundVars=Names["var*"]. I want to get all their Own, Down, and Up values and save them. I can do this with Save but that’s not quite my question. I can’t do this: DownValues/@foundVars

Example Question 2: I create a function to check symbol naming:

Attributes[checkName]=HoldAll
checkName[x_]:=StringMatchQ[SymbolName[x],"var*"]

But I run into this:

in:     var3=.;    (*Clear var3*)
in:     checkName[var3] 
out:    True   (*so far so good*)
in:     var3 = 2;  (*give var3 a value*)
in:     checkName[var3]
out:         SymbolName: Argument 2 at position 1 is expected to be a symbol

Looking at the results from DownValues, OwnValues, etc. I’m guessing the trick has something to do with HoldPattern, but I haven’t been able to piece it together. Let me know some tricks and best practices when working with symbols.

2

Try something like

In[1]:= var3 = 2;

In[2]:= ToExpression[#, InputForm, OwnValues] & /@ Names["var*"]

Out[2]= {{HoldPattern[var3] :> 2}}

In[3]:= Attributes[checkName] = HoldAll;
        checkName[x_] := StringMatchQ[SymbolName[Unevaluated[x]], "var*"]

In[5]:= checkName[var3]

Out[5]= True
3

Thank you Illian, that gives me some hints. I’ve never used the third argument of ToExpression and haven’t been able to use Unevaluated effectively. Great suggestions!

Appreciate the help!

4

if your trying to preserve them (you said “save them” generically)…

you can save the (whole session), a function, or expressions and restore them as .mx i believe. it saves all pertinent info including up/down values.

(you don’t need to extract info to “save them”)

5

This is a good tutorial on working with unevaluated expressions:

6

Awesome. I meant to ask for any kind of tutorial, class, or presentation on this topic. It’s been a mystery to me for years. Thanks for the link.