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  1. let arr = [| [|1; 2; 4 |] ;[|3; 2; 4 |] ;[|1; 7; 4 |] |]
  2. arr |> Array.concat |> Array.sort |> Seq.groupBy id |> Seq.map(fun el -> fst el,Seq.length (snd el)) 
  3. |> Seq.iter(fun x -> printfn "%d [%d]" (fst x) (snd x))
Success #stdin #stdout 0.17s 26048KB
comments (?)
stdin 
Standard input is empty
stdout 
1 [2]
2 [2]
3 [1]
4 [3]
7 [1]
https://ideone.com/P5hmtU
language:
F# (mono 4.1)
created:
10 years ago
visibility:
public

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