The membertype(x, s) function determines if there is an operand within the expression s of type x.  Given a module, it determines if there is an assigned export of type x. If so, it returns true, and false otherwise.

If a third argument 'p' is present and membertype yields true, then the position of the first x in s is assigned to p in the case of sets and lists, whereas the member instance is assigned to the name p if s is a module.  Position is determined as the index in the case of an rtable or module, and ith operand in the case of other data-structures.

$\mathrm{membertype}\left(\mathrm{integer}\,\left\{7\,3.2\,\frac{1}{2}\right\}\right)$

$\mathrm{true}$

$\mathrm{membertype}\left(\mathrm{integer}\,\left\{3.2\,\frac{1}{2}\right\}\right)$

$\mathrm{false}$

$\mathrm{membertype}\left(\mathrm{`*`}\,\left[xy\,w+u\,y\right]\,k\right)$

$\mathrm{true}$

$k$

$1$

$\mathrm{membertype}\left(\mathrm{symbol}\,f\left(1\,''a''\,x\right)\,'k'\right)$

$\mathrm{true}$

$k$

$3$

$m≔\mathbf{module}\left(\right)\mathrm{\_export}\left(e\,f\,g\right)\;e≔4\mathbf{end\; module}\:$

$\mathrm{membertype}\left(\mathrm{integer}\,m\,'p'\right)$

$\mathrm{true}$

$\mathrm{eval}\left(p\,1\right),p$

$e,4$

The membertype command was updated in Maple 2023.