regerege https://blog.hatena.ne.jp/regerege/ regerege メモ帳 https://regerege.hatenadiary.org/ F# 何故 sprintf で出来ないのだろうか。。 open System; let fn (x:int) = String.Format("{0:#,#}", x);; let fn x = let cc = [| ""; ""; ""; ","; |] let rec fn' x (s:string) = if x <= 0 then s else fn' (x/10) ((string (x%10)) + cc.[s.Length % 4] + s) fn' x "";; let fn (x:int) = let cc = [| ","; ""; ""; |] (string x).ToCh… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fregerege.hatenadiary.org%2Fentry%2F20120112%2F1326345131" title="整数をカンマ区切りの文字列で取得 - regerege メモ帳" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2012-01-12 14:12:11 rich https://regerege.hatenadiary.org/entry/20120112/1326345131 1.0 100%