:: (a -> a -> Bool) -> [a] -> [[a]] package:code-conjure

Classify values by a given comparison function.
> classifyBy (\(x,_) (y,_) -> x == y) [(1,1),(1,2),(2,1),(2,2)]
[[(1,1),(1,2)],[(2,1),(2,2)]]
(cf. classify, classifyOn)