{"id":525,"date":"2022-08-03T12:48:02","date_gmt":"2022-08-03T03:48:02","guid":{"rendered":"https:\/\/sumomo.ohwaki.jp\/wordpress\/?p=525"},"modified":"2022-08-03T12:48:02","modified_gmt":"2022-08-03T03:48:02","slug":"groupby%e3%81%ae%e3%82%b0%e3%83%ab%e3%83%bc%e3%83%94%e3%83%b3%e3%82%b0%e5%af%be%e8%b1%a1%e3%82%92%e5%8b%95%e7%9a%84%e3%81%ab%e5%a4%89%e6%9b%b4%e3%81%99%e3%82%8b","status":"publish","type":"post","link":"https:\/\/sumomo.ohwaki.jp\/wordpress\/?p=525","title":{"rendered":"GroupBy\u306e\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u5bfe\u8c61\u3092\u52d5\u7684\u306b\u5909\u66f4\u3059\u308b"},"content":{"rendered":"\n<p>.NET Linq\u3067GroupBy\u3092\u4f7f\u7528\u3057\u3066\u3001\u30af\u30a8\u30ea\u5185\u5bb9\u3092\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3059\u308b\u969b\u306b\u3001\u5834\u5408\u306b\u3088\u3063\u3066\u3001\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u5bfe\u8c61\u3092\u52d5\u7684\u306b\u5909\u66f4\u3057\u305f\u3044\u5834\u5408\u304c\u3042\u308b\u3002<\/p>\n\n\n\n<p>\u3053\u308c\u3092\u5b9f\u88c5\u3059\u308b\u306e\u306b\u4e00\u756a\u7c21\u5358\u306a\u65b9\u6cd5\u3092\u898b\u3064\u3051\u305f\u306e\u3067\u30e1\u30e2\u3002<\/p>\n\n\n\n<p>Enumerable.GroupBy\u62e1\u5f35\u30e1\u30bd\u30c3\u30c9\u306e\u30aa\u30fc\u30d0\u30fc\u30ed\u30fc\u30c9\u306e1\u3064\u306b\u3001\u4ee5\u4e0b\u306e\u7269\u304c\u3042\u308b\u3002<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism undefined-numbers lang-csharp\" data-file=\"GroupBy\u306e\u30aa\u30fc\u30d0\u30fc\u30ed\u30fc\u30c9\u306e1\u3064\" data-lang=\"C#\"><code>GroupBy&lt;TSource,TKey&gt;(IEnumerable&lt;TSource&gt;, Func&lt;TSource,TKey&gt;, IEqualityComparer&lt;TKey&gt;)<\/code><\/pre><\/div>\n\n\n\n<p>\u3053\u306e\u30aa\u30fc\u30d0\u30fc\u30ed\u30fc\u30c9\u306e\u30d1\u30e9\u30e1\u30fc\u30bf\u3001IEqualityComparer&lt;TKey>\u3092\u30a4\u30f3\u30d7\u30ea\u30e1\u30f3\u30c8\u3057\u305f\u30af\u30e9\u30b9\u3092\u4f5c\u308b\u3053\u3068\u3067\u3001\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u5358\u4f4d\u3092\u5916\u90e8\u304b\u3089\u6307\u5b9a\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308b\u3002<\/p>\n\n\n\n<p>\u4f8b\u3048\u3070\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30af\u30e9\u30b9\u306e\u30ea\u30b9\u30c8\u3092\u300c\u5e74\u300d+\u300c\u6708\u300d\u3067\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u308a\u3001\u300c\u5e74\u300d+\u300c\u6708\u300d+\u300c\u30bb\u30fc\u30eb\u30b9\u30de\u30f3\u300d\u3067\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u308a\u3057\u305f\u3044\u5834\u5408\u3001<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism undefined-numbers lang-csharp\" data-file=\"\u58f2\u4e0a\u30af\u30e9\u30b9\" data-lang=\"C#\"><code>public partial class Sales\n{\n    public int Year { get; set; }            \/\/ \u5e74\n    public int Month { get; set; }           \/\/ \u6708\n    public string SalesMan { get; set; }     \/\/ \u30bb\u30fc\u30eb\u30b9\u30de\u30f3\n    public string ProductName { get; set; }  \/\/ \u5546\u54c1\u540d\n    public long Qty { get; set; }            \/\/ \u8ca9\u58f2\u6570\n}<\/code><\/pre><\/div>\n\n\n\n<p>IEqualityComparer&lt;Sales>\u3092\u30a4\u30f3\u30d7\u30ea\u30e1\u30f3\u30c8\u3057\u3066\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30af\u30e9\u30b9\u3092\u4f5c\u308b\u3002<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism undefined-numbers lang-csharp\" data-file=\"IEqualityComparer\u306e\u5b9f\u88c5\" data-lang=\"C#\"><code>class SalesEqaulityComparer : IEqualityComparer&lt;Sales&gt; {\n    public bool useYear { get; set; }\n    public bool useMonth { get; set; }\n    public bool useSalesMan { get; set; }\n    public bool useProductName { get; set; }\n    \/\/ \u6bd4\u8f03\u65b9\u6cd5(IEqualityComparer&lt;T&gt;)\n    public bool Equals(Sales x, Sales y) {\n        if (useYear && !x.Year.Equals(y.Year)) return false;\n        if (useMonth && !x.Month.Equals(y.Month)) return false;\n        if (useSalesMan && !x.SalesMan.Equals(y.SalesMan)) return false;\n        if (useProductName && !x.ProductName.Equals(y.ProducName)) return false;\n        return true;\n    }\n    \/\/ HashCode\u306e\u53d6\u5f97(IEqualityComparer&lt;T&gt;)\n    public int GetHashCode(Sales s) {\n        int hash = 0;\n        if (useYear) hash ^= s.Year.GetHashCode();\n        if (useMonth) hash ^= s.Month.GetHashCode();\n        if (useSalesMan) hash ^= s.SalesMan.GetHashCode();\n        if (useProductName) hash ^= s.ProductName.GetHashCode();\n        return hash;\n    }\n}\n<\/code><\/pre><\/div>\n\n\n\n<p>\u5b9f\u969b\u306b\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3059\u308b\u3068\u304d\u306f\u3001\u3053\u306e\u30af\u30e9\u30b9\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u4f5c\u6210\u3057\u3001\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u3044useXXX\u306btrue\u3092\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u306b\u3088\u308a\u3001\u6307\u5b9a\u3057\u305f\u9805\u76ee\u3067\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u304c\u3067\u304d\u308b\u3002<\/p>\n\n\n\n<p>\u4f8b\u3048\u3070\u3001\u300c\u5e74\u300d,\u300c\u6708\u300d\u3067\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u3044\u5834\u5408\u306f\u3001useYear\u3068useMonth\u306btrue\u3092\u8a2d\u5b9a\u3057\u3001\u305d\u306e\u4ed6\u306ffalse\u306b\u8a2d\u5b9a\u3002\u300c\u5e74\u300d,\u300c\u6708\u300d,\u300c\u30bb\u30fc\u30eb\u30b9\u30de\u30f3\u300d\u3067\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u3044\u5834\u5408\u306f\u3001useYear,useMonth,useSalesMan\u306btrue\u3092\u8a2d\u5b9a\u3057\u3066\u3001\u305d\u306e\u4ed6\u306ffalse\u3092\u8a2d\u5b9a\u3057\u3066\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30af\u30a8\u30ea\u3092\u767a\u884c\u3059\u308b\u3002<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism undefined-numbers lang-csharp\" data-file=\"GroupBy\" data-lang=\"C#\"><code>List&lt;Sales&gt; SalesList = new SalesList();\n\u30fb\u30fb\u30fb\nvar salescomparer = new SalesEqaulityComparer();\n\/\/ \u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3057\u305f\u3044\u9805\u76ee\u306e\u6307\u5b9a\nsalescompare.useYear = true;\nsalescompare.useMonth = true;\n\u30fb\u30fb\u30fb\nvar g = SalesList.GroupBy(s=&gt;s,salescomparer);\nforeach(var itm in g) {\n\tConsole.WriteLine($&quot;{itm.First().Year},{itm.First().Month},\u30fb\u30fb\u30fb{itm.Sum(v=&gt;v.Qty)}}&quot;);\n}<\/code><\/pre><\/div>\n\n\n\n<p>\u610f\u5916\u3068\u4f7f\u3048\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>.NET Linq\u3067GroupBy\u3092\u4f7f\u7528\u3057\u3066\u3001\u30af\u30a8\u30ea\u5185\u5bb9\u3092\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3059\u308b\u969b\u306b\u3001 &hellip; <a href=\"https:\/\/sumomo.ohwaki.jp\/wordpress\/?p=525\">\u7d9a\u304d\u3092\u8aad\u3080 <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18,9,21,4],"tags":[],"class_list":["post-525","post","type-post","status-publish","format-standard","hentry","category-net","category-c","category-linq","category-4"],"_links":{"self":[{"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/525","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=525"}],"version-history":[{"count":3,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions"}],"predecessor-version":[{"id":528,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions\/528"}],"wp:attachment":[{"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=525"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sumomo.ohwaki.jp\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}