The function hasindex determines if ind is a valid index for the structure A; that is, whether A contains a value corresponding to the key ind.

If A is a table, hasindex tests whether ind is a key in the table.

If A is a module or record, hasindex tests whether ind is an export of the module.

If A is an rtable, hasindex tests whether ind is consistent with the dimensions of A. Note that ind may have fewer dimensions than A.

If A is an list, set, or string, hasindex tests whether ind is a nonzero integer whose absolute value does not exceed the length of A.

$L≔\left[''quick''\,''brown''\,''fox''\right]$

$L≔\left[''quick''\,''brown''\,''fox''\right]$

$\mathrm{hasindex}\left(L\,2\right)$

$\mathrm{true}$

$\mathrm{hasindex}\left(L\,4\right)$

$\mathrm{false}$

$M≔\mathrm{LinearAlgebra}:-\mathrm{VandermondeMatrix}\left(⟨1\,2\,3\,5⟩\right)$

$M≔\left[\begin{array}{cccc}1& 1& 1& 1\\ 1& 2& 4& 8\\ 1& 3& 9& 27\\ 1& 5& 25& 125\end{array}\right]$

$\mathrm{hasindex}\left(M\,2\,3\right)$

$\mathrm{true}$

$\mathrm{hasindex}\left(M\,3\,5\right)$

$\mathrm{false}$

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

$\mathrm{hasindex}\left(m\,e\right)$

$\mathrm{true}$

$\mathrm{hasindex}\left(m\,f\right)$

$\mathrm{false}$

$\mathrm{ds}≔\mathrm{DataSeries}\left(\left[32\,25\,42\right]\,\mathrm{labels}=\left[X\,Y\,Z\right]\right)$

$\mathrm{ds}≔\left[\begin{array}{cc}X& 32\\ Y& 25\\ Z& 42\end{array}\right]$

$\mathrm{hasindex}\left(\mathrm{ds}\,X\right)$

$\mathrm{true}$

The hasindex command was introduced in Maple 2020.

For more information on Maple 2020 changes, see Updates in Maple 2020.