{"id":40261,"date":"2025-11-03T06:35:32","date_gmt":"2025-11-03T06:35:32","guid":{"rendered":"https:\/\/www.railscarma.com\/?p=40261"},"modified":"2025-11-03T06:41:24","modified_gmt":"2025-11-03T06:41:24","slug":"%e3%83%9e%e3%82%b9%e3%82%bf%e3%83%bc%e3%83%ab%e3%83%93%e3%83%bc%e5%88%97%e6%8c%99%e5%8f%af%e8%83%bd%e3%81%aa%e5%90%84%e3%83%9e%e3%83%83%e3%83%97%e3%81%a8%e9%81%b8%e6%8a%9e","status":"publish","type":"post","link":"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/%e3%83%9e%e3%82%b9%e3%82%bf%e3%83%bc%e3%83%ab%e3%83%93%e3%83%bc%e5%88%97%e6%8c%99%e5%8f%af%e8%83%bd%e3%81%aa%e5%90%84%e3%83%9e%e3%83%83%e3%83%97%e3%81%a8%e9%81%b8%e6%8a%9e\/","title":{"rendered":"\u30de\u30b9\u30bf\u30fcRuby\u5217\u6319\u53ef\u80fd\u30d5\u30a1\u30a4\u30eb\uff1aeach\u3001map\u3001select"},"content":{"rendered":"<div data-elementor-type=\"wp-post\" data-elementor-id=\"40261\" class=\"elementor elementor-40261\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-a6fa11e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"a6fa11e\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-2dc11c6\" data-id=\"2dc11c6\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-08c4140 elementor-widget elementor-widget-text-editor\" data-id=\"08c4140\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>\u30eb\u30d3\u30fc <strong>\u30eb\u30d3\u30fc\u5217\u6319\u53ef\u80fd<\/strong> \u30e2\u30b8\u30e5\u30fc\u30eb\u306f\u3001\u8868\u73fe\u529b\u8c4a\u304b\u306a\u95a2\u6570\u578b\u53cd\u5fa9\u51e6\u7406\u3092\u652f\u3048\u308b\u5f37\u529b\u306a\u30c4\u30fc\u30eb\u3060\u3002\u306b\u6df7\u5728\u3057\u3066\u3044\u308b\u3002 <code>\u914d\u5217\u3001\u30cf\u30c3\u30b7\u30e5\u3001\u7bc4\u56f2\u3001\u96c6\u5408<\/code>, \u3068\u30ab\u30b9\u30bf\u30e0\u30fb\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u30af\u30ea\u30fc\u30f3\u3067\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u51e6\u7406\u304c\u53ef\u80fd\u306b\u306a\u308b\u3002.&nbsp;<span style=\"font-size: 16px;\">\u30a8\u30ad\u30b9\u30d1\u30fc\u30c8\u306b\u3088\u308bRuby\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306e\u5f37\u5316 <\/span><strong data-start=\"39\" data-end=\"68\" style=\"font-size: 16px;\"><a href=\"https:\/\/www.railscarma.com\/ja\/ruby-on-rails%e3%82%b3%e3%83%b3%e3%82%b5%e3%83%ab%e3%83%86%e3%82%a3%e3%83%b3%e3%82%b0\/\">Rails\u30b3\u30f3\u30b5\u30eb\u30c6\u30a3\u30f3\u30b0\u30b5\u30fc\u30d3\u30b9<\/a><\/strong><span style=\"font-size: 16px;\">, \u3088\u308a\u30af\u30ea\u30fc\u30f3\u3067\u9ad8\u6027\u80fd\u306a\u30b3\u30fc\u30c9\u306e\u305f\u3081\u306b\u3001\u5404\u30de\u30c3\u30d7\u3001\u30bb\u30ec\u30af\u30c8\u3092\u6700\u9069\u5316\u3059\u308b\u3002.<\/span><\/p>\n<article class=\"text-token-text-primary w-full focus:outline-none [--shadow-height:45px] has-data-writing-block:pointer-events-none has-data-writing-block:-mt-(--shadow-height) has-data-writing-block:pt-(--shadow-height) [&amp;:has([data-writing-block])&gt;*]:pointer-events-auto [content-visibility:auto] supports-[content-visibility:auto]:[contain-intrinsic-size:auto_100lvh] scroll-mt-[calc(var(--header-height)+min(200px,max(70px,20svh)))]\" tabindex=\"-1\" dir=\"auto\" data-turn-id=\"request-6902f6ea-1f18-8321-bec2-c21e0beed250-7\" data-testid=\"conversation-turn-74\" data-scroll-anchor=\"true\" data-turn=\"assistant\">\n<div class=\"text-base my-auto mx-auto pb-10 [--thread-content-margin:--spacing(4)] thread-sm:[--thread-content-margin:--spacing(6)] thread-lg:[--thread-content-margin:--spacing(16)] px-(--thread-content-margin)\">\n<div class=\"[--thread-content-max-width:40rem] thread-lg:[--thread-content-max-width:48rem] mx-auto max-w-(--thread-content-max-width) flex-1 group\/turn-messages focus-visible:outline-hidden relative flex w-full min-w-0 flex-col agent-turn\" tabindex=\"-1\">\n<div class=\"z-0 flex min-h-[46px] justify-start\"><\/div>\n<div class=\"mt-3 w-full empty:hidden\">\n<div class=\"text-center\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/article>\n<div aria-hidden=\"true\" data-edge=\"true\" class=\"pointer-events-none h-px w-px\"><\/div>\n<h2><strong>Ruby\u5217\u6319\u53ef\u80fd\uff1a\u57fa\u790e<\/strong><\/h2>\n<p>\u4f7f\u7528\u65b9\u6cd5 <strong>\u30eb\u30d3\u30fc\u5217\u6319\u53ef\u80fd<\/strong>, \u3092\u5b9a\u7fa9\u3057\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002 <code>\u5404<\/code>:<\/p>\n<pre>\u30eb\u30d3\u30fc\n\u30af\u30e9\u30b9 ShoppingList\n  \u30a4\u30f3\u30af\u30eb\u30fc\u30c9 Enumerable\n\n  def initialize(*items)\n    \u30a2\u30a4\u30c6\u30e0 = \u30a2\u30a4\u30c6\u30e0\n  \u7d42\u4e86\n\n  def each(&amp;block)\n    items.each(&amp;block)\n  end\nend<\/pre>\n<p>\u73fe\u5728 <code>\u30b7\u30e7\u30c3\u30d4\u30f3\u30b0\u30ea\u30b9\u30c8<\/code> \u30b5\u30dd\u30fc\u30c8 <strong>\u3059\u3079\u3066 Ruby \u5217\u6319\u53ef\u80fd<\/strong> \u306e\u30e1\u30bd\u30c3\u30c9\u304c\u3042\u308b\u3002.<\/p>\n<h2><strong>\u30eb\u30d3\u30fc\u306e\u5217\u6319\u53ef\u80fd\uff1a <\/strong><code>\u5404<\/code><strong> - \u9805\u76ee\u3054\u3068\u306b\u5b9f\u884c<\/strong><\/h2>\n<h4><strong>\u4f55 <\/strong><code>\u5404<\/code><strong> \u3069\u3046\u3060\u308d\u3046\uff1f<\/strong><\/h4>\n<p>\u3059\u3079\u3066\u306e\u8981\u7d20\u306b\u5bfe\u3057\u3066\u30d6\u30ed\u30c3\u30af\u3092\u5b9f\u884c\u3059\u308b\u3002. <strong>\u5143\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u8fd4\u3057\u307e\u3059\u3002.<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\n[1, 2, 3].each { |n| puts n * 2 }.\n# \u51fa\u529b\uff1a\n# 2\n# 4\n# 6\n# \u623b\u308a\u5024[1, 2, 3]<\/pre>\n<h4><strong>Ruby\u306eEnumerable\u3092\u4f7f\u3046\u3068\u304d <\/strong><code>\u5404<\/code><\/h4>\n<ul>\n<li>\u30ed\u30b0\u307e\u305f\u306f\u5370\u5237<\/li>\n<li>\u526f\u4f5c\u7528\u306e\u30c8\u30ea\u30ac\u30fc\uff08\u96fb\u5b50\u30e1\u30fc\u30eb\u3001API\u30b3\u30fc\u30eb\uff09<\/li>\n<li>\u5916\u90e8\u72b6\u614b\u306e\u84c4\u7a4d<\/li>\n<\/ul>\n<pre>\u30eb\u30d3\u30fc\n\u5408\u8a08 = 0\n[10, 20, 30].each { |n| total += n }.\nputs total # =&gt; 60<\/pre>\n<p><strong><em>\u843d\u3068\u3057\u7a74<\/em><\/strong><em><strong>:<\/strong> \u6c7a\u3057\u3066\u4f7f\u7528\u3057\u306a\u3044\u3053\u3068 <\/em><em><code>\u5404<\/code> \u5909\u63db\u3055\u308c\u305f\u914d\u5217\u3092\u671f\u5f85\u3059\u308b\u3002.<\/em><\/p>\n<pre>\u30eb\u30d3\u30fc\n# \u9593\u9055\u3044\n[1, 2, 3].each { |n| n * 2 }.# =&gt; [1, 2, 3] \u3067\u3059\u3002<\/pre>\n<h2><strong>\u30eb\u30d3\u30fc\u306e\u5217\u6319\u53ef\u80fd\uff1a <\/strong><code>\u5730\u56f3<\/code><strong> (\u307e\u305f\u306f <\/strong><code>\u96c6\u3081\u308b<\/code><strong>) - \u3042\u3089\u3086\u308b\u30a2\u30a4\u30c6\u30e0\u3092\u5909\u8eab\u3055\u305b\u308b<\/strong><\/h2>\n<h4><strong>\u4f55 <\/strong><code>\u5730\u56f3<\/code><strong> \u3069\u3046\u3060\u308d\u3046\uff1f<\/strong><\/h4>\n<p>\u30d6\u30ed\u30c3\u30af\u3068 <strong>\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u3059<\/strong> \u7d50\u679c\u306e.<\/p>\n<pre>\u30eb\u30d3\u30fc\n[1, 2, 3].map { |n| n * 2 }.# =&gt; [2, 4, 6].<\/pre>\n<h4><strong>Ruby\u306eEnumerable\u3092\u4f7f\u3046\u3068\u304d <\/strong><code>\u5730\u56f3<\/code><\/h4>\n<ul>\n<li>\u30c7\u30fc\u30bf\u578b\u306e\u5909\u63db<\/li>\n<li>\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u62bd\u51fa<\/li>\n<li>\u65b0\u3057\u3044\u69cb\u9020\u7269\u306e\u5efa\u8a2d<\/li>\n<\/ul>\n<h4><strong>\u30eb\u30d3\u30fc\u5217\u6319\u53ef\u80fd <\/strong><code>\u5730\u56f3<\/code><strong> \u4f8b<\/strong><\/h4>\n<p><strong>\u540d\u524d\u3092\u5927\u6587\u5b57\u306b\u3059\u308b<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\n[\"alice\", \"bob\"].map(&amp;:upcase) # =&gt; [\"ALICE\", \"BOB\"].<\/pre>\n<p><strong>\u30e6\u30fc\u30b6\u30fcE\u30e1\u30fc\u30eb\u306e\u62bd\u51fa<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\nusers = [{email: \"a@x.com\"}, {email: \"b@x.com\"}].\nusers.\u30de\u30c3\u30d7 { |u| u[:email] }.# =&gt; [\"a@x.com\", \"b@x.com\"].<\/pre>\n<p><strong>\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u4ed8\u304d<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\nfruits = [\"apple\", \"banana\"] \u30d5\u30eb\u30fc\u30c4 = [\"\u30ea\u30f3\u30b4\", \"\u30d0\u30ca\u30ca\nfruits.map.with_index { |f, i| \"#{i + 1}.#{f}\"}\n# =&gt; [\"1. \u30ea\u30f3\u30b4\", \"2. \u30d0\u30ca\u30ca\"].<\/pre>\n<p><strong><em>\u843d\u3068\u3057\u7a74<\/em><\/strong><em>:\u4f7f\u7528\u3057\u306a\u3044 <\/em><em><code>\u5730\u56f3<\/code> \u526f\u4f5c\u7528\u306e\u305f\u3081\u3060\u3051\u3067\u3042\u308b\u3002.<\/em><\/p>\n<pre>\u30eb\u30d3\u30fc\n# [nil, nil, nil] \u3092\u8fd4\u3059\u3002\n[1, 2, 3].map { |n| puts n }.<\/pre>\n<h2><strong>\u30eb\u30d3\u30fc\u306e\u5217\u6319\u53ef\u80fd\uff1a <\/strong><code>\u9078\u629e\u3059\u308b<\/code><strong> (\u307e\u305f\u306f <\/strong><code>find_all<\/code><strong>) - \u4e00\u81f4\u3059\u308b\u9805\u76ee\u3092\u30d5\u30a3\u30eb\u30bf\u30ea\u30f3\u30b0\u3059\u308b<\/strong><\/h2>\n<h4><strong>\u4f55 <\/strong><code>\u9078\u629e\u3059\u308b<\/code><strong> \u3069\u3046\u3060\u308d\u3046\uff1f<\/strong><\/h4>\n<p>\u3092\u8fd4\u3057\u307e\u3059\u3002 <strong>\u65b0\u3057\u3044\u914d\u5217<\/strong> \u30d6\u30ed\u30c3\u30af\u304c\u8fd4\u3059\u8981\u7d20\u306e <code>\u771f\u5b9f<\/code>.<\/p>\n<pre>\u30eb\u30d3\u30fc\n[1, 2, 3, 4].select(&amp;:even?) # =&gt; [2, 4].<\/pre>\n<h4><strong>Ruby\u306eEnumerable\u3092\u4f7f\u3046\u3068\u304d <\/strong><code>\u9078\u629e\u3059\u308b<\/code><\/h4>\n<ul>\n<li>\u6709\u52b9\u306a\u30ec\u30b3\u30fc\u30c9\u306e\u30d5\u30a3\u30eb\u30bf\u30ea\u30f3\u30b0<\/li>\n<li>\u30c7\u30fc\u30bf\u7167\u4f1a<\/li>\n<li>\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u30b5\u30d6\u30bb\u30c3\u30c8<\/li>\n<\/ul>\n<h4><strong>\u30eb\u30d3\u30fc\u5217\u6319\u53ef\u80fd <\/strong><code>\u9078\u629e\u3059\u308b<\/code><strong> \u4f8b<\/strong><\/h4>\n<p><strong>\u5408\u683c\u30b9\u30b3\u30a2<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\n\u30b9\u30b3\u30a2 = [89, 45, 92, 61\uff3d\nscore.select { |s| s &gt;= 70 }.# =&gt; [89, 92] \u3067\u3059\u3002<\/pre>\n<p><strong>\u30a2\u30af\u30c6\u30a3\u30d6\u30e6\u30fc\u30b6\u30fc<\/strong><\/p>\n<pre>\u30eb\u30d3\u30fc\n\u30e6\u30fc\u30b6\u30fc = [\n  {name: \"Alice\", active: true}\u3001\n  {name: \"Bob\", active: false}.\n]\nusers.select { |u| u[:active] }.# =&gt; [{name: \"Alice\", active: true}] \u3067\u3059\u3002<\/pre>\n<p><strong>\u53cd\u5bfe\u5074\uff1a <\/strong><code>\u62d2\u5426\u3059\u308b<\/code><\/p>\n<pre>\u30eb\u30d3\u30fc\n[1, 2, 3, 4].reject(&amp;:even?) # =&gt; [1, 3].<\/pre>\n<h2><strong>Ruby\u306e\u5217\u6319\u53ef\u80fd\uff1a\u4e3b\u306a\u9055\u3044<\/strong><\/h2>\n<table>\n<tbody>\n<tr>\n<th>\u65b9\u6cd5<\/th>\n<th>\u30ea\u30bf\u30fc\u30f3<\/th>\n<th>\u76ee\u7684<\/th>\n<\/tr>\n<tr>\n<td><code>\u5404<\/code><\/td>\n<td>\u30aa\u30ea\u30b8\u30ca\u30eb\u30fb\u30b3\u30ec\u30af\u30b7\u30e7\u30f3<\/td>\n<td>\u526f\u4f5c\u7528<\/td>\n<\/tr>\n<tr>\n<td><code>\u5730\u56f3<\/code><\/td>\n<td>\u5909\u63db\u3055\u308c\u305f\u5024\u306e\u65b0\u3057\u3044\u914d\u5217<\/td>\n<td>\u30c7\u30fc\u30bf\u306e\u5909\u63db<\/td>\n<\/tr>\n<tr>\n<td><code>\u9078\u629e\u3059\u308b<\/code><\/td>\n<td>\u4e00\u81f4\u3059\u308b\u8981\u7d20\u306e\u65b0\u3057\u3044\u914d\u5217<\/td>\n<td>\u30d5\u30a3\u30eb\u30bf\u30fc\u30c7\u30fc\u30bf<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><strong>Ruby\u5217\u6319\u53ef\u80fd\uff1a\u30d1\u30ef\u30fc\u306e\u9023\u9396<\/strong><\/h2>\n<p>\u8868\u73fe\u529b\u8c4a\u304b\u306a\u30d1\u30a4\u30d7\u30e9\u30a4\u30f3\u306e\u305f\u3081\u306e\u30c1\u30a7\u30fc\u30f3\u30e1\u30bd\u30c3\u30c9\uff1a<\/p>\n<pre>\u30eb\u30d3\u30fc\n(1..10)\n  .select(&amp;:even?) # [2, 4, 6, 8, 10].\n  .map { |n| n ** 2 }.   # [4, 16, 36, 64, 100] .each { |q| puts n ** 2 }.\n  .each { |sq| puts sq }.<\/pre>\n<p>\u5b9f\u4f8b\u3060\uff1a<\/p>\n<pre>\u30eb\u30d3\u30fc\nactive_emails = \u30e6\u30fc\u30b6\u30fc\n  .select { |u| u[:active] &amp;&amp; u[:age] &gt;= 18 }.\n  .\u30de\u30c3\u30d7 { |u| u[:email] }.<\/pre>\n<h2><strong>Ruby\u306e\u5217\u6319\u578b\uff1a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u30d2\u30f3\u30c8<\/strong><\/h2>\n<h4><strong>1\u30d1\u30b9 &gt; 2\u30d1\u30b9<\/strong><\/h4>\n<pre>\u30eb\u30d3\u30fc\n# \u3088\u308a\u9045\u3044\uff1a2\u56de\u306e\u7e70\u308a\u8fd4\u3057\nusers.map(&amp;:age).select { |a| a &gt; 18 }.\n\n# \u3088\u308a\u9ad8\u901f\uff1a1\u56de\u306e\u7e70\u308a\u8fd4\u3057\nusers.select { |u| u[:age] &gt; 18 }.map(&amp;:age)<\/pre>\n<h4><strong>\u8a18\u53f7\u304b\u3089\u30d7\u30ed\u30c3\u30af\u3078\u306e\u901f\u8a18\u6cd5<\/strong><\/h4>\n<pre>\u30eb\u30d3\u30fc\nnames.map(&amp;:upcase)<\/pre>\n<h4><strong>\u5927\u898f\u6a21\uff0f\u7121\u9650\u30c7\u30fc\u30bf\u306b\u5bfe\u3059\u308b\u9045\u5ef6\u8a55\u4fa1<\/strong><\/h4>\n<pre>\u30eb\u30d3\u30fc\n(1..Float::INFINITY).lazy\n  .select(&amp;:even?)\n  .map { |n| n * n }.\n  .first(5)\n# =&gt; [4, 16, 36, 64, 100].<\/pre>\n<h3><strong>Ruby\u5217\u6319\u53ef\u80fd\uff1a\u30dc\u30fc\u30ca\u30b9\u30fb\u30d1\u30bf\u30fc\u30f3<\/strong><\/h3>\n<h4><strong>\u5b89\u5168\u306a\u69cb\u6587\u89e3\u6790 <\/strong><code>\u5730\u56f3<\/code><strong> + <\/strong><code>\u30b3\u30f3\u30d1\u30af\u30c8<\/code><\/h4>\n<pre>\u30eb\u30d3\u30fc\n[\"1\", \"2\", \"abc\"].map { |s| Integer(s) rescue nil }.compact\n# =&gt; [1, 2].<\/pre>\n<h4><strong>\u6700\u521d\u306e\u30de\u30c3\u30c1\u3092\u63a2\u3059<\/strong><\/h4>\n<pre>\u30eb\u30d3\u30fc\nadmin = users.find { |u| u[:role] == \"admin\" }.  # select.first\u3088\u308a\u826f\u3044<\/pre>\n<h4><strong>\u3067\u84c4\u7a4d\u3059\u308b <\/strong><code>each_with_\u30aa\u30d6\u30b8\u30a7\u30af\u30c8<\/code><\/h4>\n<pre>\u30eb\u30d3\u30fc\n[1, 2, 3].each_with_object({}) { |n, h| h[n] = n * 2 }.\n# =&gt; {1=&gt;2, 2=&gt;4, 3=&gt;6}.<\/pre>\n<h2><strong>Ruby\u306e\u5217\u6319\u53ef\u80fd\uff1a\u6700\u7d42\u30c1\u30a7\u30c3\u30af\u30ea\u30b9\u30c8<\/strong><\/h2>\n<ul>\n<li>\u7528\u9014 <code>\u5404<\/code> \u2192 \u526f\u4f5c\u7528<\/li>\n<li>\u7528\u9014 <code>\u5730\u56f3<\/code> \u2192 \u5909\u63db<\/li>\n<li>\u7528\u9014 <code>\u9078\u629e\u3059\u308b<\/code> \u2192 \u30d5\u30a3\u30eb\u30bf\u30fc<\/li>\n<li>\u660e\u77ad\u3055\u306e\u305f\u3081\u306e\u30c1\u30a7\u30fc\u30f3<\/li>\n<li>\u623b\u308a\u5024\u3092\u7121\u8996\u3057\u306a\u3044<\/li>\n<li>\u597d\u3080 <code>\u63a2\u3059<\/code> \u30aa\u30fc\u30d0\u30fc <code>select.first<\/code><\/li>\n<li>\u7528\u9014 <code>\u3078\u305f\u308c<\/code> \u5de8\u5927\uff0f\u7121\u9650\u30b9\u30c8\u30ea\u30fc\u30e0\u7528<\/li>\n<\/ul>\n<h2><strong>\u7d50\u8ad6\uff1a<\/strong><\/h2>\n<p>Ruby\u306eEnumerable\u30e2\u30b8\u30e5\u30fc\u30eb\u306f\u5358\u306a\u308b\u30e1\u30bd\u30c3\u30c9\u96c6\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002Ruby\u306e <code>\u5404\u3001\u5730\u56f3<\/code>\u3001 \u305d\u3057\u3066 <code>\u9078\u629e\u3059\u308b<\/code>, \u305d\u3057\u3066\u3001\u6b21\u306e\u3088\u3046\u306a\u80fd\u529b\u304c\u8eab\u306b\u3064\u304f\uff1a<\/p>\n<ul>\n<li><strong>\u660e\u78ba\u306a\u610f\u601d\u8868\u793a<\/strong> - \u3082\u3046\u6df7\u4e71\u3059\u308b\u30eb\u30fc\u30d7\u306f\u306a\u3044\u3002.<\/li>\n<li><strong>\u30d0\u30b0\u3092\u907f\u3051\u308b<\/strong> - \u623b\u308a\u5024\u306f\u91cd\u8981\u3067\u3042\u308a\u3001\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u305d\u308c\u3092\u5f37\u5236\u3059\u308b\u3002.<\/li>\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f<\/strong> - \u30ef\u30f3\u30d1\u30b9\u6f14\u7b97\u3068\u9045\u5ef6\u8a55\u4fa1\u3002.<\/li>\n<li><strong style=\"font-size: 16px;\">\u30c1\u30a7\u30fc\u30f3\u6d41\u66a2<\/strong><span style=\"font-size: 16px;\"> - \u5f37\u529b\u306a\u30c7\u30fc\u30bf\u30d1\u30a4\u30d7\u30e9\u30a4\u30f3\u30921\u884c\u3067\u69cb\u7bc9\u3002.<\/span><\/li>\n<\/ul>\n<p>\u3067 <strong>\u30ec\u30fc\u30eb\u30ab\u30fc\u30de<\/strong>\u3092\u30ea\u30fc\u30c9\u3057\u3066\u3044\u308b\u3002 <a href=\"https:\/\/www.railscarma.com\/ja\">Ruby on Rails\u958b\u767a\u4f1a\u793e<\/a>, \u79c1\u305f\u3061\u306f\u3001\u30b9\u30b1\u30fc\u30e9\u30d6\u30eb\u3067\u4fdd\u5b88\u6027\u304c\u9ad8\u304f\u3001\u30a8\u30ec\u30ac\u30f3\u30c8\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u69cb\u7bc9\u3059\u308b\u305f\u3081\u306b\u3001\u65e5\u3005\u3053\u308c\u3089\u306e\u539f\u5247\u3092\u9069\u7528\u3057\u3066\u3044\u307e\u3059\u3002\u30e6\u30fc\u30b6\u30fc\u306e\u30d5\u30a3\u30eb\u30bf\u30ea\u30f3\u30b0\u3001\u30c7\u30fc\u30bf\u30bb\u30c3\u30c8\u306e\u5909\u63db\u3001\u901a\u77e5\u306e\u9001\u4fe1\u306a\u3069\u3001\u5f53\u793e\u306e\u958b\u767a\u8005\u306fRuby\u306eEnumerable\uff08\u5217\u6319\u53ef\u80fd\uff09\u306a\u30d1\u30ef\u30fc\u3092\u6d3b\u7528\u3057\u3066\u3001\u8868\u73fe\u529b\u3068\u52b9\u7387\u6027\u3092\u517c\u306d\u5099\u3048\u305f\u30b3\u30fc\u30c9\u3092\u66f8\u3044\u3066\u3044\u307e\u3059\u3002.<\/p>\n<p>\u3053\u308c\u3089\u306e\u65b9\u6cd5\u3092\u6bce\u65e5\u5b9f\u8df5\u3057\u3001\u8ce2\u304f\u9023\u9396\u3055\u305b\u308c\u3070\u3001\u3084\u304c\u3066\u3042\u306a\u305f\u306fRuby\u3092\u66f8\u304f\u3079\u304f\u3057\u3066\u66f8\u304b\u308c\u305f\u3088\u3046\u306b\u3001\u30a8\u30ec\u30ac\u30f3\u30c8\u3067\u3001\u8868\u73fe\u529b\u8c4a\u304b\u3067\u3001\u697d\u306b\u66f8\u3051\u308b\u3088\u3046\u306b\u306a\u308b\u3002.<\/p>\n<p>\u30bf\u30fc\u30df\u30ca\u30eb\u3092\u958b\u304d\u3001irb\u3092\u8d77\u52d5\u3057\u3001\u4ee5\u4e0b\u3092\u8a66\u3057\u3066\u307f\u308b\u3002 <code>\u30de\u30c3\u30d7\u3092\u9078\u629e\u3059\u308b<\/code>\u3001 \u305d\u3057\u3066 <code>\u5404<\/code> \u3069\u3093\u306a\u30a2\u30ec\u30a4\u3067\u3082\u3002\u30d1\u30ef\u30fc\u306f\u3001\u305d\u3057\u3066RailsCarma\u306e\u3084\u308a\u65b9\u306f\u3001\u3042\u306a\u305f\u306e\u624b\u306e\u4e2d\u306b\u3042\u308a\u307e\u3059\u3002.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t  <div class=\"related-post slider\">\r\n        <div class=\"headline\">\u95a2\u9023\u8a18\u4e8b<\/div>\r\n    <div class=\"post-list owl-carousel\">\r\n\r\n            <div class=\"item\">\r\n            <div class=\"thumb post_thumb\">\r\n    <a  title=\"MLOps\u306e\u305f\u3081\u306eRuby on Rails: ML\u30c7\u30d7\u30ed\u30a4\u30e1\u30f3\u30c8\u5b8c\u5168\u30ac\u30a4\u30c9\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/ruby-on-rails-for-mlops-ml%e3%83%87%e3%83%97%e3%83%ad%e3%82%a4%e3%83%a1%e3%83%b3%e3%83%88%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%89\/?related_post_from=41350\">\r\n\r\n      <img decoding=\"async\" width=\"800\" height=\"300\" src=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Ruby-on-Rails-for-MLOps.png\" class=\"attachment-full size-full wp-post-image\" alt=\"MLOps\u306e\u305f\u3081\u306eRuby on Rails\" srcset=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Ruby-on-Rails-for-MLOps.png 800w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Ruby-on-Rails-for-MLOps-300x113.png 300w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Ruby-on-Rails-for-MLOps-768x288.png 768w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Ruby-on-Rails-for-MLOps-18x7.png 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\r\n\r\n    <\/a>\r\n  <\/div>\r\n\r\n  <a class=\"title post_title\"  title=\"MLOps\u306e\u305f\u3081\u306eRuby on Rails: ML\u30c7\u30d7\u30ed\u30a4\u30e1\u30f3\u30c8\u5b8c\u5168\u30ac\u30a4\u30c9\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/ruby-on-rails-for-mlops-ml%e3%83%87%e3%83%97%e3%83%ad%e3%82%a4%e3%83%a1%e3%83%b3%e3%83%88%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%89\/?related_post_from=41350\">\r\n        MLOps\u306e\u305f\u3081\u306eRuby on Rails: ML\u30c7\u30d7\u30ed\u30a4\u30e1\u30f3\u30c8\u5b8c\u5168\u30ac\u30a4\u30c9  <\/a>\r\n\r\n        <\/div>\r\n              <div class=\"item\">\r\n            <div class=\"thumb post_thumb\">\r\n    <a  title=\"Ruby on Rails\u3067\u30a8\u30fc\u30b8\u30a7\u30f3\u30c8\u578bAI\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u69cb\u7bc9\u3059\u308b\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/building-agentic-ai-applications-with-ruby-on-rails\/?related_post_from=41339\">\r\n\r\n      <img decoding=\"async\" width=\"800\" height=\"300\" src=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Building-Agentic-AI-Applications-with-Ruby-on-Rails.png\" class=\"attachment-full size-full wp-post-image\" alt=\"Ruby on Rails\u306b\u3088\u308b\u30a8\u30fc\u30b8\u30a7\u30f3\u30c8\u578bAI\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\" srcset=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Building-Agentic-AI-Applications-with-Ruby-on-Rails.png 800w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Building-Agentic-AI-Applications-with-Ruby-on-Rails-300x113.png 300w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Building-Agentic-AI-Applications-with-Ruby-on-Rails-768x288.png 768w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/05\/Building-Agentic-AI-Applications-with-Ruby-on-Rails-18x7.png 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\r\n\r\n    <\/a>\r\n  <\/div>\r\n\r\n  <a class=\"title post_title\"  title=\"Ruby on Rails\u3067\u30a8\u30fc\u30b8\u30a7\u30f3\u30c8\u578bAI\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u69cb\u7bc9\u3059\u308b\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/building-agentic-ai-applications-with-ruby-on-rails\/?related_post_from=41339\">\r\n        Ruby on Rails\u3067\u30a8\u30fc\u30b8\u30a7\u30f3\u30c8\u578bAI\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u69cb\u7bc9\u3059\u308b  <\/a>\r\n\r\n        <\/div>\r\n              <div class=\"item\">\r\n            <div class=\"thumb post_thumb\">\r\n    <a  title=\"Offliberty Ruby Gem\u3068\u306f\uff1f\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/what-is-offliberty-ruby-gem-and-how-it-works\/?related_post_from=41304\">\r\n\r\n      <img decoding=\"async\" width=\"800\" height=\"300\" src=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/What-is-Offliberty-Ruby-Gem-and-How-It-Works.png\" class=\"attachment-full size-full wp-post-image\" alt=\"\u30aa\u30d5\u30ea\u30d0\u30c6\u30a3\u30fb\u30eb\u30d3\u30fc\u30fb\u30b8\u30a7\u30e0\" srcset=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/What-is-Offliberty-Ruby-Gem-and-How-It-Works.png 800w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/What-is-Offliberty-Ruby-Gem-and-How-It-Works-300x113.png 300w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/What-is-Offliberty-Ruby-Gem-and-How-It-Works-768x288.png 768w, https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/What-is-Offliberty-Ruby-Gem-and-How-It-Works-18x7.png 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\r\n\r\n    <\/a>\r\n  <\/div>\r\n\r\n  <a class=\"title post_title\"  title=\"Offliberty Ruby Gem\u3068\u306f\uff1f\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/what-is-offliberty-ruby-gem-and-how-it-works\/?related_post_from=41304\">\r\n        Offliberty Ruby Gem\u3068\u306f\uff1f  <\/a>\r\n\r\n        <\/div>\r\n              <div class=\"item\">\r\n            <div class=\"thumb post_thumb\">\r\n    <a  title=\"Ruby on Rails\u3092\u4f7f\u3063\u3066\u30b9\u30b1\u30fc\u30e9\u30d6\u30eb\u306aSaaS\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u3092\u69cb\u7bc9\u3059\u308b\u65b9\u6cd5\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/how-to-build-a-scalable-saas-platform-using-ruby-on-rails\/?related_post_from=41273\">\r\n\r\n      <img decoding=\"async\" width=\"800\" height=\"300\" src=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/Build-a-SaaS-Platform-Using-Ruby-on-Rails.png\" class=\"attachment-full size-full wp-post-image\" alt=\"Ruby on Rails\u3092\u4f7f\u3063\u3066SaaS\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u3092\u69cb\u7bc9\u3059\u308b\" srcset=\"https:\/\/www.railscarma.com\/wp-content\/uploads\/2026\/04\/Build-a-SaaS-Platform-Using-Ruby-on-Rails.png 800w, 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Rails\u3092\u4f7f\u3063\u3066\u30b9\u30b1\u30fc\u30e9\u30d6\u30eb\u306aSaaS\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u3092\u69cb\u7bc9\u3059\u308b\u65b9\u6cd5  <\/a>\r\n\r\n        <\/div>\r\n      \r\n  <\/div>\r\n\r\n  <script>\r\n      <\/script>\r\n  <style>\r\n    .related-post {}\r\n\r\n    .related-post .post-list {\r\n      text-align: left;\r\n          }\r\n\r\n    .related-post .post-list .item {\r\n      margin: 10px;\r\n      padding: 10px;\r\n          }\r\n\r\n    .related-post .headline {\r\n      font-size: 14px !important;\r\n      color: #999999 !important;\r\n          }\r\n\r\n    .related-post .post-list .item .post_thumb {\r\n      max-height: 220px;\r\n      margin: 10px 0px;\r\n      padding: 0px;\r\n      display: block;\r\n          }\r\n\r\n    .related-post .post-list .item .post_title {\r\n      font-size: 14px;\r\n      color: #000000;\r\n      margin: 10px 0px;\r\n      padding: 0px;\r\n      display: block;\r\n      text-decoration: none;\r\n     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Mixed into Array, Hash, Range, Set, and custom collections, it enables clean, efficient data processing.&nbsp;Enhance your Ruby projects with expert Rails consulting services, optimizing each, map, and select for cleaner, high-performance code. Ruby Enumerable: The Foundation To use Ruby Enumerable, a class must define each: ruby class ShoppingList include Enumerable def initialize(*items) &nbsp;&nbsp; @items = items end def each(&amp;block) &nbsp;&nbsp; @items.each(&amp;block) end end Now ShoppingList supports all Ruby Enumerable methods. Ruby Enumerable: each \u2013 Execute Per Item What each Does Runs a block for every element. Returns the original collection. ruby [1, 2, 3].each { |n| puts n * &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/www.railscarma.com\/ja\/%e3%83%96%e3%83%ad%e3%82%b0\/how-to-build-a-scalable-saas-platform-using-ruby-on-rails\/\"> <span class=\"screen-reader-text\">Ruby on Rails\u3092\u4f7f\u3063\u3066\u30b9\u30b1\u30fc\u30e9\u30d6\u30eb\u306aSaaS\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u3092\u69cb\u7bc9\u3059\u308b\u65b9\u6cd5<\/span> \u3082\u3063\u3068\u8aad\u3080 \"<\/a><\/p>","protected":false},"author":11,"featured_media":40294,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1224],"tags":[],"class_list":["post-40261","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Master Ruby Enumerable: each, map, and select - 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