WOLFRAM LANGUAGE TUTORIAL
Manipulating Symbols and Contexts by Name
|Symbol["name"]||construct a symbol with a given name|
|SymbolName[symb]||find the name of a symbol|
Converting between symbols and their names.
This gives the symbol x
Once you have made an assignment such as x=2, then whenever x is evaluated, it is replaced by 2. Sometimes, however, you may want to continue to refer to x itself, without immediately getting the value of x.
You can do this by referring to x by name. The name of the symbol x is the string "x", and even though x itself may be replaced by a value, the string "x" will always stay the same.
The names of the symbols x
are the strings "x"
This assigns a value to x
Whenever you enter x
it is now replaced by 2
The name "x"
is not affected, however.
|NameQ["form"]||test whether any symbol has a name which matches form|
|Names["form"]||give a list of all symbol names which match form|
|Contexts["form`"]||give a list of all context names which match form|
Referring to symbols and contexts by name.
are symbols that have been created in this Wolfram Language session; xpp
You can specify the form of symbol names using string patterns of the kind discussed in "String Patterns". "x*" stands, for example, for all names that start with x.
This gives a list of all symbol names in this Wolfram Language session that begin with x
These names correspond to built‐
in functions in the Wolfram Language.
This asks for names "close" to WeierstrssP
|Clear["form"]||clear the values of all symbols whose names match form|
|Clear["context`*"]||clear the values of all symbols in the specified context|
|Remove["form"]||remove completely all symbols whose names match form|
|Remove["context`*"]||remove completely all symbols in the specified context|
Getting rid of symbols by name.
This clears the values of all symbols whose names start with x
The name "x"
is still known, however.
But the value of x
has been cleared.
This removes completely all symbols whose names start with x
Now not even the name "x"
|Remove["Global`*"]||remove completely all symbols in the Global` context|
Removing all symbols you have introduced.
If you do not set up any additional contexts, then all the symbols that you introduce in a Wolfram Language session will be placed in the Global` context. You can remove these symbols completely using Remove["Global`*"]. Built‐in Wolfram Language objects are in the System` context, and are thus unaffected by this.