SYMVAR Find Symbolic Variables in an Expression

Usage

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.

Example

Here are some simple examples:

--> symvar('x^2+sqrt(x)')  % sqrt is eliminated as a function
ans = 
  <cell array> - size: [1 1]
 x    
--> symvar('pi+3')         % No identifiers here
ans = 
  <cell array> - size: [0 0]
  []
--> symvar('x + t*alpha')  % x, t and alpha
ans = 
  <cell array> - size: [1 3]
 
Columns 1 to 3
 alpha    t    x