The whattype(expr) function returns the data type name of expr, which may be any of the following basic data types:

Although exprseq is not a type name known to the type function, it is the name of the internal data structure for expression sequences.

For a general expression, whattype returns the "top level" data type as determined by the order of precedence of the operators.

$\mathrm{whattype}\left(x+y\right)$

$\mathrm{`+`}$

$\mathrm{whattype}\left(x-y\right)$

$\mathrm{`+`}$

$\mathrm{whattype}\left(-x\right)$

$\mathrm{`*`}$

$\mathrm{whattype}\left(x^{2}f\left(y\right)\right)$

$\mathrm{`*`}$

$\mathrm{whattype}\left(\frac{x}{y}\right)$

$\mathrm{`*`}$

$\mathrm{whattype}\left(x^y\right)$

$\mathrm{`^`}$

$\mathrm{whattype}\left(\frac{1}{x}\right)$

$\mathrm{`^`}$

$\mathrm{whattype}\left(x\,y\right)$

$\mathrm{exprseq}$

$\mathrm{whattype}\left(\left[x\,y\,z\right]\right)$

$\mathrm{list}$

$\mathrm{whattype}\left(2+4\mathrm{I}\right)$

$\mathrm{complex}\left(\mathrm{extended\_numeric}\right)$

$\mathrm{whattype}\left(a\right)$

$\mathrm{symbol}$

$a≔1\:$

$\mathrm{whattype}\left(a\right)$

$\mathrm{integer}$

$b≔''hello''\:$

$\mathrm{whattype}\left(b\right)$

$\mathrm{string}$

$M≔\mathrm{rtable}\left(\left[\left[1\,2\right]\,\left[3\,4\right]\right]\right)$

$M≔\left[\begin{array}{cc}1& 2\\ 3& 4\end{array}\right]$

$\mathrm{whattype}\left(M\right)$

$\mathrm{Array}$

$N≔\mathrm{Matrix}\left(\left[\left[1\,2\right]\,\left[3\,4\right]\right]\right)$

$N≔\left[\begin{array}{cc}1& 2\\ 3& 4\end{array}\right]$

$\mathrm{whattype}\left(N\right)$

$\mathrm{Matrix}$