The quasi-best MaxN function

[stevengj]

@rocco_sprmnt21

I have not found among the library functions a function that finds the first N maximum values of a list. I tried to define some functions and make performance comparisons.

@stevengj

This implementation, using a heap, seems to be much faster than the other ones posted here for both larger and smaller n .

Okay, I’m dumb — the DataStructures.jl package already contains such a function, implemented using heaps.

Just call nlargest(n, array) from DataStructures.jl — it seems to be faster than all of the implementations above, including mine, in all the cases above.

(It beats my code apparently because it takes advantage of the lower-level heap function DataStructures.percolate_down! … nlargest currently only supports arrays, not arbitrary iterators, but that limitation looks easy to fix if desired.)