Marshall
Created page with "'''Self-classify''', or '''index-in-nub''', is a monadic function that gives the index of each of its argument cells in the unique argument cells, which can be implemented as <syntaxhighlight lang=apl inline>{(∪⍵)⍳⍵}</syntaxhighlight> or <syntaxhighlight lang=apl inline>(∪⍳⊢)</syntaxhighlight>. This result is another representation of the boolean matrix returned by the earlier function Nub in defined by Iverson. Classify is implement..."