Is it possible to assign custom attributes to symbols and check them later?
SetAttributes[a, b] says
Attributes::attnf: b is not a known attribute. $\begingroup$ $\endgroup$
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4 No, I do not believe it is. As the documentation for your error message says:
The attributes available in each version of Mathematica are fixed and cannot be changed.
The system attributes are low level properties that fundamentally change the evaluation of symbols. I think it makes sense that these are not mixed with high-level user constructs, even though at times that would be quite convenient.
For an alternative remember that you can attach Options to a symbol, e.g.:
Options[a] = {"Attributes" -> {"b"}}; OptionValue[a, "Attributes"] {"b"}
You could also use a single DownValues rule such as:
a["Attributes"] = {"b"}; a["Attributes"] {"b"}
- $\begingroup$ Thanks. But how to change individual option of a symbol? $\endgroup$Suzan Cioc– Suzan Cioc2013-01-19 10:14:41 +00:00Commented Jan 19, 2013 at 10:14
- $\begingroup$ Ah, I found
SetOptionsfunction. $\endgroup$Suzan Cioc– Suzan Cioc2013-01-19 10:15:18 +00:00Commented Jan 19, 2013 at 10:15 - $\begingroup$ @Suzan What do you mean? It is simple to replace the list of options with either method shown, e.g.
SetOptions[a, "Attributes" -> {"c", "d"}];ora["Attributes"] = {"c", "d"};Are you asking for a way to individually append or remove these values asSetAttributesandClearAttributesdo? I could add that to my answer if you have trouble crafting it yourself. $\endgroup$Mr.Wizard– Mr.Wizard2013-01-19 10:17:32 +00:00Commented Jan 19, 2013 at 10:17 - $\begingroup$ @Suzan Thanks for the Accept, but please consider waiting a while first as someone else may have an answer you like better if you do not discourage them from reading the question. $\endgroup$Mr.Wizard– Mr.Wizard2013-01-19 10:18:26 +00:00Commented Jan 19, 2013 at 10:18