{"id":1267,"date":"2025-03-24T08:52:27","date_gmt":"2025-03-23T23:52:27","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=1267"},"modified":"2025-03-24T08:52:27","modified_gmt":"2025-03-23T23:52:27","slug":"ruby-dig%e3%83%a1%e3%82%bd%e3%83%83%e3%83%89%e5%ae%8c%e5%85%a8%e3%83%9e%e3%82%b9%e3%82%bf%e3%83%bc%ef%bc%9a5%e3%81%a4%e3%81%ae%e5%ae%9f%e8%b7%b5%e7%9a%84%e3%81%aa%e4%bd%bf%e3%81%84%e6%96%b9%e3%81%a8","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=1267","title":{"rendered":"Ruby dig\u30e1\u30bd\u30c3\u30c9\u5b8c\u5168\u30de\u30b9\u30bf\u30fc\uff1a5\u3064\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u3044\u65b9\u3068\u5931\u6557\u3057\u306a\u3044\u30b3\u30c4"},"content":{"rendered":"\n<div class=\"toc\"><br \/>\n<b>Warning<\/b>:  Undefined array key \"is_admin\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>116<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_category_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>121<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>128<\/b><br \/>\n    <div id=\"toc_container\" class=\"sgb-toc--bullets js-smooth-scroll\" data-dialog-title=\"\u76ee\u6b21\">\n      <p class=\"toc_title\">\u76ee\u6b21 <\/p>\n      <ul class=\"toc_list\">  <li class=\"first\">    <a href=\"#i-0\">Ruby\u306edig\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1a\u5b89\u5168\u306a\u30c7\u30fc\u30bf\u30a2\u30af\u30bb\u30b9\u306e\u65b0\u6a19\u6e96<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-1\">\u5f93\u6765\u306e\u30cf\u30c3\u30b7\u30e5\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5\u306e\u8ab2\u984c\u3068\u9650\u754c<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-2\">dig\u30e1\u30bd\u30c3\u30c9\u304c\u89e3\u6c7a\u3059\u308b3\u3064\u306e\u554f\u984c\u70b9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-3\">dig\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-4\">\u30b7\u30f3\u30d7\u30eb\u306a\u30cf\u30c3\u30b7\u30e5\u3067\u306edig\u6d3b\u7528\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-5\">\u914d\u5217\u3092\u542b\u3080\u30cd\u30b9\u30c8\u5316\u3055\u308c\u305f\u30c7\u30fc\u30bf\u3067\u306e\u64cd\u4f5c\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-6\">\u5b9f\u8df5\u7684\u306adig\u30e1\u30bd\u30c3\u30c9\u306e\u6d3b\u7528\u30d1\u30bf\u30fc\u30f3<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-7\">API\u30ec\u30b9\u30dd\u30f3\u30b9\u306e\u5b89\u5168\u306a\u51e6\u7406\u65b9\u6cd5<\/a>      <\/li>      <li>        <a href=\"#i-8\">\u8a2d\u5b9a\u30d5\u30a1\u30a4\u30eb\u306e\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u53d6\u5f97\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-9\">JSON\u30c7\u30fc\u30bf\u89e3\u6790\u3067\u306e\u52b9\u7387\u7684\u306a\u4f7f\u3044\u65b9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-10\">dig\u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u6ce8\u610f\u70b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-11\">\u5f93\u6765\u306e\u65b9\u6cd5\u3068\u51e6\u7406\u901f\u5ea6\u6bd4\u8f03<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-12\">\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316\u624b\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-13\">dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3063\u305f\u5b9f\u88c5\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-14\">Rails \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u306eAPI\u51e6\u7406\u30d1\u30bf\u30fc\u30f3<\/a>      <\/li>      <li>        <a href=\"#i-15\">\u30c6\u30b9\u30c8\u3057\u3084\u3059\u3044dig\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u3044\u65b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-16\">\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u306e\u305f\u3081\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/a>      <\/li>    <\/ul>  <\/li><\/ul>\n      <a href=\"#\" class=\"sgb-toc-button js-toc-button\" rel=\"nofollow\" data-open-dialog=\"true\"><i class=\"fa fa-list\"><\/i><span class=\"sgb-toc-button__text\">\u76ee\u6b21\u3078<\/span><\/a>\n    <\/div><\/div><h2 class=\"wp-block-heading\" id=\"i-0\">Ruby\u306edig\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1a\u5b89\u5168\u306a\u30c7\u30fc\u30bf\u30a2\u30af\u30bb\u30b9\u306e\u65b0\u6a19\u6e96<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-1\">\u5f93\u6765\u306e\u30cf\u30c3\u30b7\u30e5\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5\u306e\u8ab2\u984c\u3068\u9650\u754c<\/h3>\n\n\n\n<p>Ruby\u3067\u30cd\u30b9\u30c8\u3055\u308c\u305f\u30cf\u30c3\u30b7\u30e5\u3084\u30c7\u30fc\u30bf\u69cb\u9020\u3092\u6271\u3046\u969b\u3001\u5f93\u6765\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u65b9\u6cd5\u3067\u30c7\u30fc\u30bf\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3066\u3044\u307e\u3057\u305f\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">user_data = {\n  profile: {\n    contact: {\n      email: \"example@email.com\"\n    }\n  }\n}\n\n# \u5f93\u6765\u306e\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5\nemail = user_data[:profile][:contact][:email]<\/pre>\n\n\n\n<p>\u3053\u306e\u65b9\u6cd5\u306b\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u91cd\u5927\u306a\u8ab2\u984c\u304c\u3042\u308a\u307e\u3057\u305f\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>NIL\u30a8\u30e9\u30fc\u306e\u30ea\u30b9\u30af<\/strong>\uff1a<br>\u4e2d\u9593\u306e\u30cf\u30c3\u30b7\u30e5\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u3001<code>NoMethodError: undefined method '[]' for nil:NilClass<\/code>\u304c\u767a\u751f\u3057\u307e\u3059\u3002<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">user_data = { profile: {} }\n# \u4ee5\u4e0b\u306e\u30b3\u30fc\u30c9\u306f\u30a8\u30e9\u30fc\u306b\u306a\u308a\u307e\u3059\nemail = user_data[:profile][:contact][:email]  # =&gt; NoMethodError<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u5197\u9577\u306a\u30ac\u30fc\u30c9\u7bc0\u306e\u5fc5\u8981\u6027<\/strong>\uff1a<br>\u5b89\u5168\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u305f\u3081\u306b\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u5197\u9577\u306a\u30b3\u30fc\u30c9\u304c\u5fc5\u8981\u3067\u3057\u305f\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">email = user_data &amp;&amp; \n        user_data[:profile] &amp;&amp; \n        user_data[:profile][:contact] &amp;&amp; \n        user_data[:profile][:contact][:email]<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u4f4e\u4e0b<\/strong>\uff1a<br>\u30ac\u30fc\u30c9\u7bc0\u304c\u5897\u3048\u308b\u3053\u3068\u3067\u3001\u672c\u6765\u306e\u30ed\u30b8\u30c3\u30af\u304c\u898b\u3065\u3089\u304f\u306a\u3063\u3066\u3057\u307e\u3044\u307e\u3059\u3002<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">dig\u30e1\u30bd\u30c3\u30c9\u304c\u89e3\u6c7a\u3059\u308b3\u3064\u306e\u554f\u984c\u70b9<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u4e0a\u8a18\u306e\u8ab2\u984c\u3092\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u89e3\u6c7a\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u5b89\u5168\u306a\u30a2\u30af\u30bb\u30b9<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># nil\u304c\u8fd4\u3055\u308c\u308b\u3060\u3051\u3067\u3001\u30a8\u30e9\u30fc\u306f\u767a\u751f\u3057\u307e\u305b\u3093\nemail = user_data.dig(:profile, :contact, :email)  # =&gt; nil<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u30b7\u30f3\u30d7\u30eb\u306a\u8a18\u8ff0<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e00\u884c\u3067\u30cd\u30b9\u30c8\u3055\u308c\u305f\u5024\u306b\u30a2\u30af\u30bb\u30b9\u53ef\u80fd<\/li>\n\n\n\n<li>\u4e2d\u9593\u306e\u30c1\u30a7\u30c3\u30af\u304c\u4e0d\u8981<\/li>\n\n\n\n<li>\u30e1\u30bd\u30c3\u30c9\u30c1\u30a7\u30fc\u30f3\u304c\u7c21\u6f54<\/li>\n<\/ul>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u578b\u5b89\u5168\u6027\u306e\u5411\u4e0a<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u9014\u4e2d\u306e\u8981\u7d20\u304c\u914d\u5217\u3084\u30cf\u30c3\u30b7\u30e5\u3067\u306a\u3044\u5834\u5408\u3082\u5b89\u5168\u306b\u51e6\u7406\ninvalid_data = { profile: \"not_a_hash\" }\nresult = invalid_data.dig(:profile, :contact)  # =&gt; nil<\/pre>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u306e\u4e3b\u306a\u7279\u5fb4\uff1a<\/p>\n\n\n<div id=\"id-b807a16f-ff73-4f58-809f-af5478ad496e\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7279\u5fb4<\/th><th>\u8aac\u660e<\/th><\/tr><\/thead><tbody><tr><td>\u623b\u308a\u5024<\/td><td>\u898b\u3064\u304b\u3063\u305f\u5024\u307e\u305f\u306fnil<\/td><\/tr><tr><td>\u5f15\u6570<\/td><td>\u53ef\u5909\u9577\u3067\u8907\u6570\u306e\u30ad\u30fc\u3092\u53d7\u3051\u53d6\u308a\u53ef\u80fd<\/td><\/tr><tr><td>\u5bfe\u5fdc\u578b<\/td><td>Hash, Array, Struct\u7b49\u306b\u5bfe\u5fdc<\/td><\/tr><tr><td>Ruby\u5bfe\u5fdc<\/td><td>Ruby 2.3\u4ee5\u964d\u3067\u6a19\u6e96\u5b9f\u88c5<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001dig\u30e1\u30bd\u30c3\u30c9\u306f\u5f93\u6765\u306e\u30c7\u30fc\u30bf\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5\u306e\u554f\u984c\u3092\u89e3\u6c7a\u3057\u3001\u3088\u308a\u5b89\u5168\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u305f\u3081\u306e\u65b0\u3057\u3044\u6a19\u6e96\u3068\u306a\u3063\u3066\u3044\u307e\u3059\u3002\u7279\u306bAPI\u30ec\u30b9\u30dd\u30f3\u30b9\u3084JSON\u5f62\u5f0f\u306e\u30c7\u30fc\u30bf\u3092\u6271\u3046\u73fe\u4ee3\u306eWeb\u958b\u767a\u306b\u304a\u3044\u3066\u3001\u305d\u306e\u4fa1\u5024\u306f\u975e\u5e38\u306b\u9ad8\u3044\u3082\u306e\u3068\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-3\">dig\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-4\">\u30b7\u30f3\u30d7\u30eb\u306a\u30cf\u30c3\u30b7\u30e5\u3067\u306edig\u6d3b\u7528\u6cd5<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u69cb\u6587\u306f\u4ee5\u4e0b\u306e\u901a\u308a\u3067\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">hash.dig(key1, key2, key3, ...)<\/pre>\n\n\n\n<p>\u5b9f\u969b\u306e\u4f7f\u7528\u4f8b\u3092\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u30b7\u30f3\u30d7\u30eb\u306a\u30cd\u30b9\u30c8\u3055\u308c\u305f\u30cf\u30c3\u30b7\u30e5\nconfig = {\n  database: {\n    production: {\n      host: \"db.example.com\",\n      port: 5432,\n      credentials: {\n        username: \"admin\",\n        password: \"secret\"\n      }\n    }\n  }\n}\n\n# \u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u30db\u30b9\u30c8\u540d\u3092\u53d6\u5f97\nhost = config.dig(:database, :production, :host)\n# =&gt; \"db.example.com\"\n\n# \u5b58\u5728\u3057\u306a\u3044\u30d1\u30b9\u3078\u306e\u30a2\u30af\u30bb\u30b9\ninvalid_path = config.dig(:database, :development, :host)\n# =&gt; nil \uff08\u30a8\u30e9\u30fc\u3067\u306f\u306a\u304fnil\u304c\u8fd4\u3055\u308c\u308b\uff09\n\n# \u30cd\u30b9\u30c8\u3055\u308c\u305f\u8a8d\u8a3c\u60c5\u5831\u3078\u306e\u30a2\u30af\u30bb\u30b9\nusername = config.dig(:database, :production, :credentials, :username)\n# =&gt; \"admin\"<\/pre>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u306e\u7279\u5fb4\u7684\u306a\u4f7f\u3044\u65b9\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u8a2d\u5b9a<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># nil\u306e\u5834\u5408\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3092\u8a2d\u5b9a\nhost = config.dig(:database, :staging, :host) || \"localhost\"\n# =&gt; \"localhost\"<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u6761\u4ef6\u5206\u5c90\u3068\u306e\u7d44\u307f\u5408\u308f\u305b<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">if config.dig(:database, :production, :host)\n  # \u30db\u30b9\u30c8\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u308b\u5834\u5408\u306e\u51e6\u7406\nelse\n  # \u30db\u30b9\u30c8\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u306a\u3044\u5834\u5408\u306e\u51e6\u7406\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-5\">\u914d\u5217\u3092\u542b\u3080\u30cd\u30b9\u30c8\u5316\u3055\u308c\u305f\u30c7\u30fc\u30bf\u3067\u306e\u64cd\u4f5c\u65b9\u6cd5<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u306f\u914d\u5217\u8981\u7d20\u3078\u306e\u30a2\u30af\u30bb\u30b9\u3082\u30b5\u30dd\u30fc\u30c8\u3057\u3066\u3044\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u914d\u5217\u3092\u542b\u3080\u30cd\u30b9\u30c8\u3055\u308c\u305f\u30c7\u30fc\u30bf\u69cb\u9020\nuser_data = {\n  users: [\n    {\n      id: 1,\n      contacts: [\n        { type: \"email\", value: \"user1@example.com\" },\n        { type: \"phone\", value: \"123-456-7890\" }\n      ]\n    },\n    {\n      id: 2,\n      contacts: [\n        { type: \"email\", value: \"user2@example.com\" }\n      ]\n    }\n  ]\n}\n\n# \u914d\u5217\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u4f7f\u7528\u3057\u305f\u30a2\u30af\u30bb\u30b9\nfirst_user_email = user_data.dig(:users, 0, :contacts, 0, :value)\n# =&gt; \"user1@example.com\"\n\n# \u914d\u5217\u3068\u30cf\u30c3\u30b7\u30e5\u306e\u6df7\u5728\u3057\u305f\u30d1\u30b9\u3078\u306e\u30a2\u30af\u30bb\u30b9\nsecond_user_email = user_data.dig(:users, 1, :contacts, 0, :value)\n# =&gt; \"user2@example.com\"<\/pre>\n\n\n\n<p>\u5b9f\u8df5\u7684\u306a\u30c6\u30af\u30cb\u30c3\u30af\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u591a\u6bb5\u968e\u306e\u914d\u5217\u30a2\u30af\u30bb\u30b9<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]\nvalue = matrix.dig(1, 2)  # =&gt; 6<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>nil\u30bb\u30fc\u30d5\u306a\u30e1\u30bd\u30c3\u30c9\u30c1\u30a7\u30fc\u30f3<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u30e1\u30bd\u30c3\u30c9\u30c1\u30a7\u30fc\u30f3\u3067\u306e\u6d3b\u7528\nresult = user_data.dig(:users, 0, :contacts)&amp;.find { |c| c[:type] == \"phone\" }&amp;.dig(:value)\n# =&gt; \"123-456-7890\"<\/pre>\n\n\n<div id=\"id-7b8ab0bd-4f92-4c4b-aa79-c95e45027f19\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u64cd\u4f5c\u5bfe\u8c61<\/th><th>dig\u306e\u4f7f\u3044\u65b9<\/th><th>\u6ce8\u610f\u70b9<\/th><\/tr><\/thead><tbody><tr><td>\u30cf\u30c3\u30b7\u30e5<\/td><td>\u30b7\u30f3\u30dc\u30eb\u307e\u305f\u306f\u6587\u5b57\u5217\u30ad\u30fc<\/td><td>\u30ad\u30fc\u306e\u578b\u306f\u7d71\u4e00\u3059\u308b<\/td><\/tr><tr><td>\u914d\u5217<\/td><td>\u6570\u5024\u30a4\u30f3\u30c7\u30c3\u30af\u30b9<\/td><td>\u7bc4\u56f2\u5916\u306f<code>nil<\/code>\u3092\u8fd4\u3059<\/td><\/tr><tr><td>\u6df7\u5728\u30c7\u30fc\u30bf<\/td><td>\u30ad\u30fc\u3068\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u9806\u306b\u6307\u5b9a<\/td><td>\u9806\u5e8f\u3092\u6b63\u78ba\u306b\u628a\u63e1\u3059\u308b<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001dig\u30e1\u30bd\u30c3\u30c9\u306f\u5358\u7d14\u306a\u30cf\u30c3\u30b7\u30e5\u304b\u3089\u8907\u96d1\u306a\u914d\u5217\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\u307e\u3067\u3001\u69d8\u3005\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u306b\u5bfe\u3057\u3066\u67d4\u8edf\u306b\u5bfe\u5fdc\u3067\u304d\u307e\u3059\u3002\u7279\u306b\u6df1\u3044\u30cd\u30b9\u30c8\u3092\u6301\u3064\u69cb\u9020\u3084\u3001\u52d5\u7684\u306b\u69cb\u9020\u304c\u5909\u308f\u308b\u53ef\u80fd\u6027\u306e\u3042\u308b\u30c7\u30fc\u30bf\u3092\u6271\u3046\u969b\u306b\u3001\u305d\u306e\u771f\u4fa1\u3092\u767a\u63ee\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-6\">\u5b9f\u8df5\u7684\u306adig\u30e1\u30bd\u30c3\u30c9\u306e\u6d3b\u7528\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-7\">API\u30ec\u30b9\u30dd\u30f3\u30b9\u306e\u5b89\u5168\u306a\u51e6\u7406\u65b9\u6cd5<\/h3>\n\n\n\n<p>API\u30ec\u30b9\u30dd\u30f3\u30b9\u306e\u51e6\u7406\u306f\u3001dig\u30e1\u30bd\u30c3\u30c9\u304c\u6700\u3082\u5a01\u529b\u3092\u767a\u63ee\u3059\u308b\u5834\u9762\u306e\u4e00\u3064\u3067\u3059\u3002<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">require 'json'\nrequire 'net\/http'\n\n# API\u30ec\u30b9\u30dd\u30f3\u30b9\u306e\u4f8b\nresponse = {\n  \"data\": {\n    \"user\": {\n      \"details\": {\n        \"name\": \"John Doe\",\n        \"location\": {\n          \"city\": \"Tokyo\",\n          \"country\": \"Japan\"\n        }\n      },\n      \"preferences\": {\n        \"notifications\": {\n          \"email\": true,\n          \"push\": false\n        }\n      }\n    }\n  },\n  \"meta\": {\n    \"status\": 200\n  }\n}\n\n# \u5b89\u5168\u306a\u30c7\u30fc\u30bf\u53d6\u5f97\u306e\u4f8b\nclass APIClient\n  def get_user_location(response)\n    # \u8907\u6570\u968e\u5c64\u306e\u30c7\u30fc\u30bf\u3092\u5b89\u5168\u306b\u53d6\u5f97\n    city = response.dig(:data, :user, :details, :location, :city)\n    country = response.dig(:data, :user, :details, :location, :country)\n\n    return \"#{city}, #{country}\" if city &amp;&amp; country\n    \"Location not available\"\n  end\n\n  def notification_enabled?(response, type)\n    # \u6761\u4ef6\u5206\u5c90\u3068\u7d44\u307f\u5408\u308f\u305b\u305f\u4f7f\u7528\u4f8b\n    response.dig(:data, :user, :preferences, :notifications, type.to_sym) || false\n  end\nend\n\nclient = APIClient.new\nlocation = client.get_user_location(response)\n# =&gt; \"Tokyo, Japan\"\n\nemail_enabled = client.notification_enabled?(response, :email)\n# =&gt; true<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-8\">\u8a2d\u5b9a\u30d5\u30a1\u30a4\u30eb\u306e\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u53d6\u5f97\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n\n\n\n<p>\u8907\u96d1\u306a\u8a2d\u5b9a\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u306e\u5024\u306e\u53d6\u5f97\u3082\u3001dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3046\u3053\u3068\u3067\u7c21\u6f54\u306b\u66f8\u3051\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u591a\u968e\u5c64\u306e\u8a2d\u5b9a\u30d5\u30a1\u30a4\u30eb\u306e\u4f8b\nconfig = {\n  environment: {\n    development: {\n      database: {\n        primary: {\n          adapter: \"postgresql\",\n          host: \"localhost\",\n          port: 5432\n        },\n        replica: {\n          adapter: \"postgresql\",\n          host: \"replica.local\",\n          port: 5432\n        }\n      },\n      cache: {\n        redis: {\n          url: \"redis:\/\/localhost:6379\/0\"\n        }\n      }\n    }\n  }\n}\n\nclass ConfigManager\n  def initialize(config)\n    @config = config\n  end\n\n  def get_database_config(environment, db_type)\n    # \u74b0\u5883\u3068\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u30bf\u30a4\u30d7\u306b\u57fa\u3065\u3044\u3066\u8a2d\u5b9a\u3092\u53d6\u5f97\n    @config.dig(:environment, environment.to_sym, :database, db_type.to_sym) || {}\n  end\n\n  def get_cache_url(environment)\n    # \u30ad\u30e3\u30c3\u30b7\u30e5URL\u306e\u53d6\u5f97\u3068\u4ee3\u66ff\u5024\u306e\u8a2d\u5b9a\n    @config.dig(:environment, environment.to_sym, :cache, :redis, :url) || \n      \"redis:\/\/localhost:6379\/0\"\n  end\nend\n\nmanager = ConfigManager.new(config)\ndb_config = manager.get_database_config(:development, :primary)\n# =&gt; { adapter: \"postgresql\", host: \"localhost\", port: 5432 }<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-9\">JSON\u30c7\u30fc\u30bf\u89e3\u6790\u3067\u306e\u52b9\u7387\u7684\u306a\u4f7f\u3044\u65b9<\/h3>\n\n\n\n<p>JSON API\u306e\u30ec\u30b9\u30dd\u30f3\u30b9\u3092\u51e6\u7406\u3059\u308b\u969b\u306e\u5b9f\u8df5\u7684\u306a\u30d1\u30bf\u30fc\u30f3\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class JSONProcessor\n  def self.process_nested_json(json_data)\n    # JSON\u6587\u5b57\u5217\u3092\u30d1\u30fc\u30b9\u3057\u3066Ruby\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u5909\u63db\n    data = JSON.parse(json_data, symbolize_names: true)\n\n    # \u8907\u6570\u306e\u5024\u3092\u4e00\u5ea6\u306b\u5b89\u5168\u306b\u53d6\u5f97\n    {\n      user_name: data.dig(:response, :user, :name),\n      email: data.dig(:response, :user, :contact, :email),\n      address: extract_address(data)\n    }\n  end\n\n  private\n\n  def self.extract_address(data)\n    # \u4f4f\u6240\u95a2\u9023\u306e\u60c5\u5831\u3092\u96c6\u7d04\u3059\u308b\u4f8b\n    address_data = data.dig(:response, :user, :address)\n    return nil unless address_data\n\n    [\n      address_data.dig(:street),\n      address_data.dig(:city),\n      address_data.dig(:country)\n    ].compact.join(\", \")\n  end\nend\n\n# \u4f7f\u7528\u4f8b\njson_string = '{\"response\":{\"user\":{\"name\":\"Jane Doe\",\"contact\":{\"email\":\"jane@example.com\"},\"address\":{\"street\":\"123 Ruby St\",\"city\":\"Rails City\",\"country\":\"Rubyland\"}}}}'\nresult = JSONProcessor.process_nested_json(json_string)\n# =&gt; {\n#      user_name: \"Jane Doe\",\n#      email: \"jane@example.com\",\n#      address: \"123 Ruby St, Rails City, Rubyland\"\n#    }<\/pre>\n\n\n\n<p>\u5b9f\u8df5\u7684\u306adig\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u7528\u30d1\u30bf\u30fc\u30f3\u307e\u3068\u3081\uff1a<\/p>\n\n\n<div id=\"id-e970d67e-708d-4ef8-ab22-9834b80d03dc\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u30e6\u30fc\u30b9\u30b1\u30fc\u30b9<\/th><th>\u5229\u70b9<\/th><th>\u5b9f\u88c5\u306e\u30dd\u30a4\u30f3\u30c8<\/th><\/tr><\/thead><tbody><tr><td>API\u30ec\u30b9\u30dd\u30f3\u30b9\u51e6\u7406<\/td><td>\u30a8\u30e9\u30fc\u56de\u907f\u3001\u7c21\u6f54\u306a\u30b3\u30fc\u30c9<\/td><td>\u30ec\u30b9\u30dd\u30f3\u30b9\u69cb\u9020\u306e\u628a\u63e1\u3001\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u8a2d\u5b9a<\/td><\/tr><tr><td>\u8a2d\u5b9a\u7ba1\u7406<\/td><td>\u67d4\u8edf\u306a\u8a2d\u5b9a\u30a2\u30af\u30bb\u30b9<\/td><td>\u74b0\u5883\u3054\u3068\u306e\u5206\u96e2\u3001\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u63d0\u4f9b<\/td><\/tr><tr><td>JSON\u51e6\u7406<\/td><td>\u5b89\u5168\u306a\u30c7\u30fc\u30bf\u62bd\u51fa<\/td><td>\u30ad\u30fc\u306e\u6b63\u898f\u5316\u3001null\u5b89\u5168\u6027\u306e\u78ba\u4fdd<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u8907\u96d1\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u3092\u6301\u3064\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u3082\u3001\u5b89\u5168\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-10\">dig\u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u6ce8\u610f\u70b9<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-11\">\u5f93\u6765\u306e\u65b9\u6cd5\u3068\u51e6\u7406\u901f\u5ea6\u6bd4\u8f03<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u3068\u5f93\u6765\u306e\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6bd4\u8f03\u3057\u3066\u307f\u307e\u3057\u3087\u3046\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">require 'benchmark'\n\n# \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u6e96\u5099\ndata = {\n  level1: {\n    level2: {\n      level3: {\n        value: \"test\"\n      }\n    }\n  }\n}\n\nn = 1_000_000 # 100\u4e07\u56de\u5b9f\u884c\n\nBenchmark.bmbm do |x|\n  x.report(\"\u5f93\u6765\u306e\u65b9\u6cd5\") do\n    n.times do\n      value = data[:level1][:level2][:level3][:value]\n    end\n  end\n\n  x.report(\"&amp;.\u6f14\u7b97\u5b50\") do\n    n.times do\n      value = data&amp;.dig(:level1)&amp;.dig(:level2)&amp;.dig(:level3)&amp;.dig(:value)\n    end\n  end\n\n  x.report(\"dig\u30e1\u30bd\u30c3\u30c9\") do\n    n.times do\n      value = data.dig(:level1, :level2, :level3, :value)\n    end\n  end\nend\n\n# \u5b9f\u884c\u7d50\u679c\u4f8b\uff1a\n#                  user     system      total        real\n# \u5f93\u6765\u306e\u65b9\u6cd5   0.320000   0.000000   0.320000   (0.323457)\n# &amp;.\u6f14\u7b97\u5b50     0.580000   0.000000   0.580000   (0.576839)\n# dig\u30e1\u30bd\u30c3\u30c9  0.420000   0.000000   0.420000   (0.424592)<\/pre>\n\n\n\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03\u306e\u7d50\u679c\uff1a<\/p>\n\n\n<div id=\"id-81b422bb-92ed-485b-bfca-5c50092566d5\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u30a2\u30af\u30bb\u30b9\u65b9\u6cd5<\/th><th>\u76f8\u5bfe\u7684\u306a\u901f\u5ea6<\/th><th>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf<\/th><th>\u5b89\u5168\u6027<\/th><\/tr><\/thead><tbody><tr><td>\u5f93\u6765\u306e\u65b9\u6cd5<\/td><td>\u6700\u901f<\/td><td>\u6700\u5c0f<\/td><td>\u4f4e<\/td><\/tr><tr><td>dig\u30e1\u30bd\u30c3\u30c9<\/td><td>\u3084\u3084\u9045\u3044<\/td><td>\u4e2d\u7a0b\u5ea6<\/td><td>\u9ad8<\/td><\/tr><tr><td>&amp;.\u6f14\u7b97\u5b50<\/td><td>\u6700\u3082\u9045\u3044<\/td><td>\u6700\u5927<\/td><td>\u9ad8<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-12\">\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316\u624b\u6cd5<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u3092\u52b9\u7387\u7684\u306b\u4f7f\u7528\u3059\u308b\u305f\u3081\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4e0d\u8981\u306a\u30c1\u30a7\u30fc\u30f3\u306e\u56de\u907f<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u60aa\u3044\u4f8b\uff1a\u5197\u9577\u306a\u30c1\u30a7\u30fc\u30f3\nresult = data.dig(:key1)&amp;.dig(:key2)&amp;.dig(:key3)\n\n# \u826f\u3044\u4f8b\uff1a1\u56de\u306edig\u3067\u5b8c\u7d50\nresult = data.dig(:key1, :key2, :key3)<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u6d3b\u7528<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ConfigReader\n  def initialize(config)\n    @config = config\n    @cache = {}\n  end\n\n  def get_nested_value(*keys)\n    cache_key = keys.join('.')\n    @cache[cache_key] ||= @config.dig(*keys)\n  end\nend<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30e1\u30e2\u30ea\u52b9\u7387\u306e\u826f\u3044\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class DataProcessor\n  # \u5de8\u5927\u306a\u30cf\u30c3\u30b7\u30e5\u3092\u6271\u3046\u5834\u5408\u306e\u52b9\u7387\u7684\u306a\u5b9f\u88c5\n  def process_large_data(data)\n    needed_value = data.dig(:deeply, :nested, :specific, :value)\n    # \u5fc5\u8981\u306a\u5024\u3092\u53d6\u5f97\u5f8c\u3001\u5143\u306e\u30c7\u30fc\u30bf\u306f\u89e3\u653e\n    data = nil\n    GC.start if needed_value # \u5fc5\u8981\u306b\u5fdc\u3058\u3066GC\u3092\u5b9f\u884c\n\n    process_value(needed_value)\n  end\nend<\/pre>\n\n\n\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u305f\u3081\u306e\u30dd\u30a4\u30f3\u30c8\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30a2\u30af\u30bb\u30b9\u983b\u5ea6\u306e\u8003\u616e<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u983b\u7e41\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u5024\u306f\u5909\u6570\u306b\u30ad\u30e3\u30c3\u30b7\u30e5<\/li>\n\n\n\n<li>\u4e00\u5ea6\u3057\u304b\u4f7f\u308f\u306a\u3044\u5024\u306f\u76f4\u63a5dig\u3092\u4f7f\u7528<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u6df1\u3055\u306e\u5236\u5fa1<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u6df1\u3059\u304e\u308b\u30cd\u30b9\u30c8\u306f\u907f\u3051\u308b\n# \u60aa\u3044\u4f8b\nvery_nested = data.dig(:l1, :l2, :l3, :l4, :l5, :l6)\n\n# \u826f\u3044\u4f8b\uff1a\u4e2d\u9593\u30c7\u30fc\u30bf\u3092\u5206\u5272\u3057\u3066\u53d6\u5f97\nintermediate = data.dig(:l1, :l2, :l3)\nresult = intermediate&amp;.dig(:l4, :l5, :l6)<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u9632\u6b62<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class DataHandler\n  def handle_stream(data_stream)\n    data_stream.each do |chunk|\n      value = chunk.dig(:important, :data)\n      process(value)\n      # \u4e0d\u8981\u306a\u30c7\u30fc\u30bf\u306f\u660e\u793a\u7684\u306b\u89e3\u653e\n      chunk = nil\n    end\n  end\nend<\/pre>\n\n\n\n<p>\u6ce8\u610f\u3059\u3079\u304d\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\uff1a<\/p>\n\n\n<div id=\"id-7ba25afa-6d5c-449f-8209-5494630237b0\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u30d1\u30bf\u30fc\u30f3<\/th><th>\u554f\u984c\u70b9<\/th><th>\u5bfe\u7b56<\/th><\/tr><\/thead><tbody><tr><td>\u904e\u5ea6\u306e\u30cd\u30b9\u30c8<\/td><td>\u30e1\u30f3\u30c6\u30ca\u30f3\u30b9\u6027\u4f4e\u4e0b<\/td><td>\u30c7\u30fc\u30bf\u69cb\u9020\u306e\u898b\u76f4\u3057<\/td><\/tr><tr><td>\u983b\u7e41\u306adig\u547c\u3073\u51fa\u3057<\/td><td>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u4f4e\u4e0b<\/td><td>\u7d50\u679c\u306e\u30ad\u30e3\u30c3\u30b7\u30e5<\/td><\/tr><tr><td>\u5927\u304d\u306a\u30c7\u30fc\u30bf\u69cb\u9020<\/td><td>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u5897\u52a0<\/td><td>\u5fc5\u8981\u306a\u90e8\u5206\u306e\u307f\u62bd\u51fa<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u3053\u308c\u3089\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001dig\u30e1\u30bd\u30c3\u30c9\u306e\u5229\u4fbf\u6027\u3092\u6d3b\u304b\u3057\u306a\u304c\u3089\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30e1\u30e2\u30ea\u52b9\u7387\u306e\u826f\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-13\">dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3063\u305f\u5b9f\u88c5\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-14\">Rails \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u306eAPI\u51e6\u7406\u30d1\u30bf\u30fc\u30f3<\/h3>\n\n\n\n<p>Rails\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067API\u30ec\u30b9\u30dd\u30f3\u30b9\u3092\u51e6\u7406\u3059\u308b\u969b\u306e\u5b9f\u8df5\u7684\u306a\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u3092\u7d39\u4ecb\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># app\/services\/api_response_handler.rb\nclass ApiResponseHandler\n  class &lt;&lt; self\n    def handle_response(response)\n      # \u30ec\u30b9\u30dd\u30f3\u30b9\u3092\u5b89\u5168\u306b\u51e6\u7406\u3059\u308b\u30b5\u30fc\u30d3\u30b9\u30af\u30e9\u30b9\n      {\n        status: extract_status(response),\n        data: extract_data(response),\n        errors: extract_errors(response)\n      }\n    end\n\n    private\n\n    def extract_status(response)\n      response.dig(:meta, :status) || 500\n    end\n\n    def extract_data(response)\n      response.dig(:data, :attributes) || {}\n    end\n\n    def extract_errors(response)\n      response.dig(:errors)&amp;.map { |error| \n        error.dig(:detail) \n      }&amp;.compact || []\n    end\n  end\nend\n\n# app\/controllers\/users_controller.rb\nclass UsersController &lt; ApplicationController\n  def show\n    response = UserApiClient.fetch_user(params[:id])\n    result = ApiResponseHandler.handle_response(response)\n\n    if result[:status] == 200\n      @user = User.new(result[:data])\n    else\n      flash[:error] = result[:errors].join(\", \")\n      redirect_to root_path\n    end\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-15\">\u30c6\u30b9\u30c8\u3057\u3084\u3059\u3044dig\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u3044\u65b9<\/h3>\n\n\n\n<p>dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u30b3\u30fc\u30c9\u306e\u30c6\u30b9\u30bf\u30d3\u30ea\u30c6\u30a3\u3092\u5411\u4e0a\u3055\u305b\u308b\u5b9f\u88c5\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># app\/services\/config_service.rb\nclass ConfigService\n  def initialize(config_hash)\n    @config = config_hash\n  end\n\n  def get_database_url(environment)\n    @config.dig(:database, environment.to_sym, :url) || \n      fallback_database_url(environment)\n  end\n\n  private\n\n  def fallback_database_url(environment)\n    case environment.to_sym\n    when :development then \"postgres:\/\/localhost:5432\"\n    when :test then \"postgres:\/\/localhost:5432\/test\"\n    else raise \"No fallback URL for #{environment}\"\n    end\n  end\nend\n\n# spec\/services\/config_service_spec.rb\nRSpec.describe ConfigService do\n  let(:config_hash) do\n    {\n      database: {\n        production: { url: \"postgres:\/\/prod-db:5432\" },\n        staging: { url: \"postgres:\/\/staging-db:5432\" }\n      }\n    }\n  end\n\n  subject { described_class.new(config_hash) }\n\n  describe \"#get_database_url\" do\n    context \"when URL exists in config\" do\n      it \"returns the configured URL\" do\n        expect(subject.get_database_url(:production))\n          .to eq(\"postgres:\/\/prod-db:5432\")\n      end\n    end\n\n    context \"when URL doesn't exist\" do\n      it \"returns fallback URL for development\" do\n        expect(subject.get_database_url(:development))\n          .to eq(\"postgres:\/\/localhost:5432\")\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-16\">\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u306e\u305f\u3081\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/h3>\n\n\n\n<p>\u65e2\u5b58\u30b3\u30fc\u30c9\u3092dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3063\u3066\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u3059\u308b\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># Before: \u8907\u96d1\u3067\u7406\u89e3\u3057\u3065\u3089\u3044\u30b3\u30fc\u30c9\nclass UserPreferences\n  def initialize(user_data)\n    @data = user_data\n  end\n\n  def email_notification_enabled?\n    return false unless @data &amp;&amp; @data[:preferences]\n    return false unless @data[:preferences][:notifications]\n    @data[:preferences][:notifications][:email] == true\n  end\n\n  def get_theme_color\n    if @data &amp;&amp; @data[:preferences] &amp;&amp; \n       @data[:preferences][:theme] &amp;&amp; \n       @data[:preferences][:theme][:color]\n      @data[:preferences][:theme][:color]\n    else\n      \"default\"\n    end\n  end\nend\n\n# After: dig\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u305f\u7c21\u6f54\u306a\u5b9f\u88c5\nclass UserPreferences\n  def initialize(user_data)\n    @data = user_data\n  end\n\n  def email_notification_enabled?\n    @data.dig(:preferences, :notifications, :email) || false\n  end\n\n  def get_theme_color\n    @data.dig(:preferences, :theme, :color) || \"default\"\n  end\nend<\/pre>\n\n\n\n<p>\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\uff1a<\/p>\n\n\n<div id=\"id-ef7697c3-a9a8-42d7-b77c-e0dc7def8d76\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u30d1\u30bf\u30fc\u30f3<\/th><th>\u30e1\u30ea\u30c3\u30c8<\/th><th>\u4f7f\u7528\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>\u30b5\u30fc\u30d3\u30b9\u30af\u30e9\u30b9\u5316<\/td><td>\u8cac\u52d9\u306e\u5206\u96e2\u3001\u518d\u5229\u7528\u6027\u306e\u5411\u4e0a<\/td><td>API\u5fdc\u7b54\u51e6\u7406\u3001\u8a2d\u5b9a\u7ba1\u7406<\/td><\/tr><tr><td>\u5024\u30aa\u30d6\u30b8\u30a7\u30af\u30c8<\/td><td>\u4e0d\u5909\u6027\u306e\u4fdd\u8a3c\u3001\u30c9\u30e1\u30a4\u30f3\u30ed\u30b8\u30c3\u30af\u306e\u30ab\u30d7\u30bb\u30eb\u5316<\/td><td>\u30e6\u30fc\u30b6\u30fc\u8a2d\u5b9a\u3001\u30b7\u30b9\u30c6\u30e0\u8a2d\u5b9a<\/td><\/tr><tr><td>Null Object\u30d1\u30bf\u30fc\u30f3<\/td><td>nil\u78ba\u8a8d\u306e\u524a\u6e1b\u3001\u6761\u4ef6\u5206\u5c90\u306e\u7c21\u7d20\u5316<\/td><td>\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u63d0\u4f9b<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u5b9f\u88c5\u6642\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u9069\u5207\u306a\u8a2d\u5b9a<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ApplicationConfig\n  def initialize(config_hash)\n    @config = config_hash\n  end\n\n  def get_setting(key_path)\n    *path, final_key = key_path.split('.')\n    @config.dig(*path.map(&amp;:to_sym))&amp;.dig(final_key.to_sym) || \n      default_settings[key_path]\n  end\n\n  private\n\n  def default_settings\n    {\n      'api.timeout' =&gt; 30,\n      'api.retry_count' =&gt; 3,\n      'cache.enabled' =&gt; true\n    }\n  end\nend<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u306e\u7d71\u4e00<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">module SafeDigAccessible\n  def safe_dig(hash, *keys)\n    hash.dig(*keys)\n  rescue TypeError =&gt; e\n    Rails.logger.error(\"Invalid dig access: #{e.message}\")\n    nil\n  end\nend<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5<\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class CachedConfigReader\n  include SafeDigAccessible\n\n  def initialize\n    @cache = {}\n  end\n\n  def get_config(*keys)\n    cache_key = keys.join('.')\n    @cache[cache_key] ||= safe_dig(load_config, *keys)\n  end\nend<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u4fdd\u5b88\u6027\u304c\u9ad8\u304f\u3001\u30c6\u30b9\u30c8\u304c\u5bb9\u6613\u3067\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u826f\u3044\u30b3\u30fc\u30c9\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Warning: Undefined array key &#8220;is_admin&#8221; in 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<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":{"0":"post-1267","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-ruby","7":"nothumb"},"_links":{"self":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1267","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1267"}],"version-history":[{"count":1,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1267\/revisions"}],"predecessor-version":[{"id":1269,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1267\/revisions\/1269"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1267"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1267"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1267"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}