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Wolfram Language Symbolic Computations

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

Eric Smith

Eric Smith, Assured Flow Solutions, LLC.

Posted 7 years ago

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.

POSTED BY: Eric Smith

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Anonymous User

Posted 7 years ago

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")

POSTED BY: Anonymous User

Ilian Gachevski

Ilian Gachevski, Wolfram Research

Posted 7 years ago

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

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

POSTED BY: Ilian Gachevski