Function: math[retrieve] - selection from a list or set
Calling Sequence:
retrieve(l, yes, no)
Parameters:
l
- a set or list
yes
- a list or set with expressions
no
- (optional) a list or set with expressions
Description:
The function returns those elements from a list or set l that include all the expressions in yes.
Optionally you may pass a list or set as the third argument to function retrieve with all those expressions that shall not be selected.
Expressions may be algebraic expressions, or names functions.
Examples:
> with(math):
> readlib(trigsubs):
> r := trigsubs(tan(x^2-1));
Retrieve those expression(s) that contain(s) the functions 'sin' and 'cos' and the expression
:
> retrieve(r, [sin, cos, x^2-1]);
Now retrieve those expressions from r that contain the tan function but not the cot function and also not the term
:
> retrieve(r, [tan], [cot, 1/2*x^2-1/2]);
See Also:
select , has .
Version History:
Version 1.0 as of January 01, 1998