{"title":"Hash#invert\u306e\u3001\u5024\u3092\u4e0a\u66f8\u304d\u3057\u306a\u3044\u3084\u3064","provider_url":"https://hatena.blog","type":"rich","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fcookies.hatenablog.jp%2Fentry%2F2013%2F10%2F19%2F234231\" title=\"Hash#invert\u306e\u3001\u5024\u3092\u4e0a\u66f8\u304d\u3057\u306a\u3044\u3084\u3064 - cookies.txt\u3000\u3000\u3000\u3000\u3000\u3000.scr\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","blog_url":"https://cookies.hatenablog.jp/","height":"190","provider_name":"Hatena Blog","blog_title":"cookies.txt\u3000\u3000\u3000\u3000\u3000\u3000.scr","description":"{a:1, b:1, c:2}.invert # => {1=>:b, 2=>:c}:a\u3055\u3093\u304c\u6ce3\u3044\u3061\u3083\u3044\u307e\u3059\u3002Hash[*{a:1, b:1, c:2}.group_by{|k,v| v}.map{|v,kv| [v,kv.map{|k,v| k}]}.flatten(1)] # => {1=>[:a, :b], 2=>[:c]}\u3088\u304b\u3063\u305f\u306d\uff01:a\u3055\u3093\uff01","author_name":"cookie-s","categories":[],"image_url":null,"url":"https://cookies.hatenablog.jp/entry/2013/10/19/234231","width":"100%","version":"1.0","author_url":"https://blog.hatena.ne.jp/cookie-s/","published":"2013-10-19 23:42:31"}