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FreeMat
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Section: Function Related Functions
Finds the symbolic variables in an expression. The syntax for its use is
syms = symvar(expr)
where expr is a string containing an expression, such as 'x^2 + cos(t+alpha)'. The result is a cell array of strings containing the non-function identifiers in the expression. Because they are usually not used as identifiers in expressions, the strings 'pi','inf','nan','eps','i','j' are ignored.
Here are some simple examples:
--> symvar('x^2+sqrt(x)') % sqrt is eliminated as a function
ans =
[x]
--> symvar('pi+3') % No identifiers here
ans =
Empty array 0x1
--> symvar('x + t*alpha') % x, t and alpha
ans =
[alpha]
[t]
[x]