10/02/14 21:09:11
>>711
// F#
let countCommodities cs hs =
let cnt = hs |> Seq.countBy id |> Map.ofSeq
List.map (fun c -> (c, defaultArg (Map.tryFind c cnt) 0)) cs
let commodities = ["お菓子"; "お弁当"; "飲み物"]
let salesHistory = ["飲み物"; "お菓子"; "お弁当"; "お菓子";
"お菓子"; "飲み物"; "お弁当"; "お弁当"]
countCommodities commodities salesHistory