The AreDuplicate command returns a DataSeries of type truefalseFAIL where the elements correspond to true if the given element has duplicates in the DataSeries and false if the element is unique.

The output from the AreDuplicate command can be used to index a DataSeries or DataFrame in order to return the duplicate elements in a given column.

$\mathrm{DS}≔\mathrm{DataSeries}\left(⟨1\,2\,3\,3\,4\,5\,5\,5⟩\right)$

$\mathrm{DS}≔\left[\begin{array}{cc}1& 1\\ 2& 2\\ 3& 3\\ 4& 3\\ 5& 4\\ 6& 5\\ 7& 5\\ 8& 5\end{array}\right]$

$\mathrm{AreDuplicate}\left(\mathrm{DS}\right)$

$\left[\begin{array}{cc}1& \mathrm{false}\\ 2& \mathrm{false}\\ 3& \mathrm{true}\\ 4& \mathrm{true}\\ 5& \mathrm{false}\\ 6& \mathrm{true}\\ 7& \mathrm{true}\\ 8& \mathrm{true}\end{array}\right]$

$\mathrm{DS}\left[\mathrm{AreDuplicate}\left(\mathrm{DS}\right)\right]$

$\left[\begin{array}{cc}3& 3\\ 4& 3\\ 6& 5\\ 7& 5\\ 8& 5\end{array}\right]$

$\mathrm{DF}≔\mathrm{DataFrame}\left(⟨⟨1\,1\,2\,3\,3\,4⟩\left|⟨5\,3\,6\,2\,1\,4⟩\right|⟨6\,5\,1\,4\,9\,9⟩|⟨4\,2\,1\,7\,8\,3⟩⟩\right)$

$\mathrm{DF}≔\left[\begin{array}{ccccc}& 1& 2& 3& 4\\ 1& 1& 5& 6& 4\\ 2& 1& 3& 5& 2\\ 3& 2& 6& 1& 1\\ 4& 3& 2& 4& 7\\ 5& 3& 1& 9& 8\\ 6& 4& 4& 9& 3\end{array}\right]$

$\mathrm{DF}\left[\mathrm{AreDuplicate}\left(\mathrm{DF}\left[1\right]\right)\right]$

$\left[\begin{array}{ccccc}& 1& 2& 3& 4\\ 1& 1& 5& 6& 4\\ 2& 1& 3& 5& 2\\ 4& 3& 2& 4& 7\\ 5& 3& 1& 9& 8\end{array}\right]$

DF[ AreDuplicate( DF[1] ) and DF[1] >~ 2 ];

$\left[\begin{array}{ccccc}& 1& 2& 3& 4\\ 4& 3& 2& 4& 7\\ 5& 3& 1& 9& 8\end{array}\right]$

The DataSeries/AreDuplicate command was introduced in Maple 2016.

For more information on Maple 2016 changes, see Updates in Maple 2016.