The Collect( L ) function produces a list of pairs [ expr, f ] from the input list L, for which expr is an expression occurring in L and f is the (positive) integral number of occurrences of expr in L.

Note that the order of the output is session dependent, and is therefore not defined.

$\mathrm{with}\left(\mathrm{ListTools}\right)\:$

$\mathrm{Collect}\left(\left[\right]\right)$

$\mathrm{Collect}\left(\left[3\right]\right)$

$\left[\left[3\,1\right]\right]$

$\mathrm{Collect}\left(\left[2\,2\,3\,2\,4\,2\,3\,5\,4\right]\right)$

$\left[\left[2\,4\right]\,\left[3\,2\right]\,\left[4\,2\right]\,\left[5\,1\right]\right]$

The ListTools[Collect] command was introduced in Maple 2017.

For more information on Maple 2017 changes, see Updates in Maple 2017.