{"id":1286,"date":"2025-03-24T08:52:26","date_gmt":"2025-03-23T23:52:26","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=1286"},"modified":"2025-03-24T08:52:26","modified_gmt":"2025-03-23T23:52:26","slug":"%e5%88%9d%e5%bf%83%e8%80%85%e3%81%a7%e3%82%82%e3%82%8f%e3%81%8b%e3%82%8b%ef%bc%81ruby%e3%81%aefind%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%e8%ac%9b","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=1286","title":{"rendered":"\u521d\u5fc3\u8005\u3067\u3082\u308f\u304b\u308b\uff01Ruby\u306efind\u30e1\u30bd\u30c3\u30c9\u5b8c\u5168\u30de\u30b9\u30bf\u30fc\u8b1b\u5ea72024\u5e74\u7248"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\" id=\"i-0\">Ruby \u306efind\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f \u57fa\u790e\u304b\u3089\u89e3\u8aac<\/h1>\n\n\n\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 \u306efind\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f \u57fa\u790e\u304b\u3089\u89e3\u8aac<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-1\">find\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3068\u623b\u308a\u5024\u306e\u7279\u5fb4<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-4\">\u914d\u5217\u3068Enumerable\u3067\u4f7f\u3048\u308bfind\u30e1\u30bd\u30c3\u30c9\u306e\u9055\u3044<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-8\">find\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u65b9\u6cd5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-9\">\u6570\u5024\u306e\u691c\u7d22\uff1a\u6761\u4ef6\u306b\u4e00\u81f4\u3059\u308b\u6700\u521d\u306e\u8981\u7d20\u3092\u898b\u3064\u3051\u308b<\/a>      <\/li>      <li>        <a href=\"#i-10\">\u6587\u5b57\u5217\u306e\u691c\u7d22\uff1a\u90e8\u5206\u4e00\u81f4\u3068\u5b8c\u5168\u4e00\u81f4\u306e\u5b9f\u88c5\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-11\">\u30cf\u30c3\u30b7\u30e5\u304b\u3089\u306e\u691c\u7d22\uff1a\u30ad\u30fc\u3068\u5024\u3092\u4f7f\u3063\u305f\u63a2\u7d22\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-12\">find\u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-13\">\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u3067\u306efind\u30e1\u30bd\u30c3\u30c9\u306e\u52b9\u7387\u7684\u306a\u4f7f\u3044\u65b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-16\">find_all\u3084select\u3068\u306e\u4f7f\u3044\u5206\u3051\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-20\">\u5b9f\u52d9\u3067\u4f7f\u3048\u308bfind\u30e1\u30bd\u30c3\u30c9\u306e\u5fdc\u7528\u4f8b<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-21\">ActiveRecord\u3068\u7d44\u307f\u5408\u308f\u305b\u305f\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u691c\u7d22<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-24\">\u8907\u96d1\u306a\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u9ad8\u5ea6\u306a\u691c\u7d22\u306e\u5b9f\u88c5\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-28\">find\u30e1\u30bd\u30c3\u30c9\u306e\u3088\u304f\u3042\u308b\u30a8\u30e9\u30fc\u3068\u5bfe\u51e6\u6cd5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-29\">nil\u30a8\u30e9\u30fc\u306e\u539f\u56e0\u3068\u9069\u5207\u306a\u51e6\u7406\u4f8b\u5916\u306e\u5b9f\u88c5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-32\">\u30d6\u30ed\u30c3\u30af\u4f7f\u7528\u6642\u306e\u6ce8\u610f\u70b9\u3068\u30c7\u30d0\u30c3\u30b0\u306e\u30b3\u30c4<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-36\">Ruby\u306efind\u30e1\u30bd\u30c3\u30c9\u5b8c\u5168\u30de\u30b9\u30bf\u30fc\u8b1b\u5ea7\u306e\u307e\u3068\u3081<\/a>  <\/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-1\">find\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3068\u623b\u308a\u5024\u306e\u7279\u5fb4<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u306f\u3001Ruby\u306e\u914d\u5217\u3084Enumerable\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u542b\u307e\u308c\u308b\u8981\u7d20\u3092\u691c\u7d22\u3059\u308b\u305f\u3081\u306e\u5f37\u529b\u306a\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u4e0e\u3048\u3089\u308c\u305f\u6761\u4ef6\u306b\u6700\u521d\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u3092\u8fd4\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">\u57fa\u672c\u69cb\u6587<\/h3>\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=\"\"># \u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\narray.find { |element| \u6761\u4ef6\u5f0f }\n\n# \u30a8\u30a4\u30ea\u30a2\u30b9\u3068\u3057\u3066detect\u3082\u4f7f\u7528\u53ef\u80fd\narray.detect { |element| \u6761\u4ef6\u5f0f }<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-3\">\u5177\u4f53\u7684\u306a\u4f7f\u7528\u4f8b<\/h3>\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=\"\">numbers = [1, 3, 5, 7, 9, 11]\n\n# \u6700\u521d\u306e\u5076\u6570\u3092\u63a2\u3059\nresult = numbers.find { |num| num.even? }\nputs result  # =&gt; nil\uff08\u5076\u6570\u304c\u5b58\u5728\u3057\u306a\u3044\u305f\u3081\uff09\n\n# 7\u3088\u308a\u5927\u304d\u3044\u6570\u3092\u63a2\u3059\nresult = numbers.find { |num| num &gt; 7 }\nputs result  # =&gt; 9\uff08\u6761\u4ef6\u306b\u6700\u521d\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\uff09<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-4\">\u914d\u5217\u3068Enumerable\u3067\u4f7f\u3048\u308bfind\u30e1\u30bd\u30c3\u30c9\u306e\u9055\u3044<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\uff08Array\uff09\u3068Enumerable\u30e2\u30b8\u30e5\u30fc\u30eb\u3092\u30a4\u30f3\u30af\u30eb\u30fc\u30c9\u3057\u305f\u30af\u30e9\u30b9\u306e\u4e21\u65b9\u3067\u4f7f\u7528\u3067\u304d\u307e\u3059\u304c\u3001\u305d\u308c\u305e\u308c\u306b\u7279\u5fb4\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-5\">\u914d\u5217\u3067\u306e\u4f7f\u7528<\/h3>\n\n\n\n<p>\u914d\u5217\u3067find\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u30d9\u30fc\u30b9\u306e\u30a2\u30af\u30bb\u30b9\u304c\u53ef\u80fd\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=\"\"># \u914d\u5217\u3067\u306e\u4f7f\u7528\u4f8b\nfruits = [\"apple\", \"banana\", \"orange\", \"grape\"]\n\n# \u6587\u5b57\u6570\u304c6\u6587\u5b57\u306e\u679c\u7269\u3092\u63a2\u3059\nlong_fruit = fruits.find { |fruit| fruit.length == 6 }\nputs long_fruit  # =&gt; \"banana\"\n\n# find_index\u3092\u4f7f\u7528\u3057\u3066\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u53d6\u5f97\nindex = fruits.find_index { |fruit| fruit.length == 6 }\nputs index  # =&gt; 1<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-6\">Enumerable\u3067\u306e\u4f7f\u7528<\/h3>\n\n\n\n<p>Enumerable\u30e2\u30b8\u30e5\u30fc\u30eb\u3092\u30a4\u30f3\u30af\u30eb\u30fc\u30c9\u3057\u305f\u30af\u30e9\u30b9\u3067\u306f\u3001\u3088\u308a\u67d4\u8edf\u306a\u691c\u7d22\u304c\u53ef\u80fd\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=\"\"># \u30cf\u30c3\u30b7\u30e5\u3067\u306e\u4f7f\u7528\u4f8b\nuser_ages = {\n  \"John\" =&gt; 25,\n  \"Alice\" =&gt; 30,\n  \"Bob\" =&gt; 35\n}\n\n# 30\u6b73\u4ee5\u4e0a\u306e\u30e6\u30fc\u30b6\u30fc\u3092\u63a2\u3059\nresult = user_ages.find { |name, age| age &gt;= 30 }\nputs result.inspect  # =&gt; [\"Alice\", 30]\n\n# Range\u3067\u306e\u4f7f\u7528\u4f8b\nrange = (1..100)\n# \u6700\u521d\u306e3\u306e\u500d\u6570\u3092\u63a2\u3059\nfirst_multiple_of_three = range.find { |num| num % 3 == 0 }\nputs first_multiple_of_three  # =&gt; 3<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-7\">find\u30e1\u30bd\u30c3\u30c9\u306e\u623b\u308a\u5024\u306e\u7279\u5fb4<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6761\u4ef6\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u304c\u3042\u308b\u5834\u5408\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6700\u521d\u306b\u4e00\u81f4\u3057\u305f\u8981\u7d20\u3092\u8fd4\u3057\u307e\u3059<\/li>\n\n\n\n<li>\u914d\u5217\u306e\u5834\u5408\u306f\u8981\u7d20\u81ea\u4f53\u3092\u8fd4\u3057\u307e\u3059<\/li>\n\n\n\n<li>\u30cf\u30c3\u30b7\u30e5\u306e\u5834\u5408\u306f[key, value]\u306e\u914d\u5217\u3092\u8fd4\u3057\u307e\u3059<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6761\u4ef6\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u304c\u306a\u3044\u5834\u5408\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>nil\u3092\u8fd4\u3057\u307e\u3059<\/li>\n\n\n\n<li>\u30d6\u30ed\u30c3\u30af\u3092\u7701\u7565\u3057\u305f\u5834\u5408\u306fEnumerator\u3092\u8fd4\u3057\u307e\u3059<\/li>\n<\/ul>\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=\"\"># \u6761\u4ef6\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u304c\u306a\u3044\u5834\u5408\nnumbers = [1, 3, 5, 7]\nresult = numbers.find { |num| num &gt; 10 }\nputs result  # =&gt; nil\n\n# \u30d6\u30ed\u30c3\u30af\u3092\u7701\u7565\u3057\u305f\u5834\u5408\nenumerator = numbers.find\nputs enumerator.class  # =&gt; Enumerator<\/pre>\n\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001find\u30e1\u30bd\u30c3\u30c9\u306f\u67d4\u8edf\u3067\u5f37\u529b\u306a\u691c\u7d22\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u3001\u69d8\u3005\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u4f7f\u7528\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3088\u308a\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"i-8\">find\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u65b9\u6cd5<\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-9\">\u6570\u5024\u306e\u691c\u7d22\uff1a\u6761\u4ef6\u306b\u4e00\u81f4\u3059\u308b\u6700\u521d\u306e\u8981\u7d20\u3092\u898b\u3064\u3051\u308b<\/h2>\n\n\n\n<p>\u6570\u5024\u30c7\u30fc\u30bf\u306e\u691c\u7d22\u306f\u3001find\u30e1\u30bd\u30c3\u30c9\u306e\u6700\u3082\u4e00\u822c\u7684\u306a\u4f7f\u7528\u4f8b\u306e\u4e00\u3064\u3067\u3059\u3002\u8907\u96d1\u306a\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u67d4\u8edf\u306a\u691c\u7d22\u304c\u53ef\u80fd\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=\"\">numbers = [10, 25, 33, 47, 52, 68, 71, 89, 95]\n\n# \u8907\u6570\u306e\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u691c\u7d22\n# 50\u3088\u308a\u5927\u304d\u304f\u3001\u304b\u3064\u5076\u6570\u306e\u6700\u521d\u306e\u8981\u7d20\u3092\u63a2\u3059\nresult = numbers.find { |num| num &gt; 50 &amp;&amp; num.even? }\nputs result  # =&gt; 52\n\n# \u7bc4\u56f2\u3092\u4f7f\u3063\u305f\u691c\u7d22\n# 30\u304b\u308960\u306e\u7bc4\u56f2\u5185\u3067\u30017\u306e\u500d\u6570\u3092\u63a2\u3059\nresult = numbers.find { |num| (30..60).include?(num) &amp;&amp; num % 7 == 0 }\nputs result  # =&gt; nil\uff08\u8a72\u5f53\u3059\u308b\u8981\u7d20\u304c\u306a\u3044\uff09\n\n# \u3088\u308a\u8907\u96d1\u306a\u6761\u4ef6\u3067\u306e\u691c\u7d22\n# \u5e73\u65b9\u6839\u304c\u6574\u6570\u3068\u306a\u308b\u6700\u521d\u306e\u8981\u7d20\u3092\u63a2\u3059\nresult = numbers.find { |num| Math.sqrt(num) % 1 == 0 }\nputs result  # =&gt; 25<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-10\">\u6587\u5b57\u5217\u306e\u691c\u7d22\uff1a\u90e8\u5206\u4e00\u81f4\u3068\u5b8c\u5168\u4e00\u81f4\u306e\u5b9f\u88c5\u65b9\u6cd5<\/h2>\n\n\n\n<p>\u6587\u5b57\u5217\u306e\u691c\u7d22\u3067\u306f\u3001\u5b8c\u5168\u4e00\u81f4\u3001\u90e8\u5206\u4e00\u81f4\u3001\u6b63\u898f\u8868\u73fe\u306a\u3069\u3001\u69d8\u3005\u306a\u65b9\u6cd5\u3067\u6761\u4ef6\u3092\u6307\u5b9a\u3067\u304d\u307e\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=\"\">words = [\"Ruby\", \"Python\", \"JavaScript\", \"Ruby on Rails\", \"React\", \"Angular\"]\n\n# \u5b8c\u5168\u4e00\u81f4\u3067\u306e\u691c\u7d22\nexact_match = words.find { |word| word == \"Ruby\" }\nputs exact_match  # =&gt; \"Ruby\"\n\n# \u90e8\u5206\u4e00\u81f4\u3067\u306e\u691c\u7d22\uff08include?\u3092\u4f7f\u7528\uff09\npartial_match = words.find { |word| word.include?(\"Script\") }\nputs partial_match  # =&gt; \"JavaScript\"\n\n# \u6b63\u898f\u8868\u73fe\u3092\u4f7f\u7528\u3057\u305f\u691c\u7d22\nregex_match = words.find { |word| word =~ \/^R.*y$\/ }\nputs regex_match  # =&gt; \"Ruby\"\n\n# \u6587\u5b57\u6570\u3068\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u691c\u7d22\ncomplex_match = words.find { |word| word.length &gt; 5 &amp;&amp; word.downcase.include?('r') }\nputs complex_match  # =&gt; \"Ruby on Rails\"<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-11\">\u30cf\u30c3\u30b7\u30e5\u304b\u3089\u306e\u691c\u7d22\uff1a\u30ad\u30fc\u3068\u5024\u3092\u4f7f\u3063\u305f\u63a2\u7d22\u30c6\u30af\u30cb\u30c3\u30af<\/h2>\n\n\n\n<p>\u30cf\u30c3\u30b7\u30e5\u30c7\u30fc\u30bf\u306e\u691c\u7d22\u3067\u306f\u3001\u30ad\u30fc\u3068\u5024\u306e\u4e21\u65b9\u3092\u4f7f\u3063\u3066\u6761\u4ef6\u3092\u6307\u5b9a\u3067\u304d\u307e\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=\"\">users = {\n  \"user1\" =&gt; { name: \"John Smith\", age: 28, role: \"developer\" },\n  \"user2\" =&gt; { name: \"Alice Brown\", age: 34, role: \"manager\" },\n  \"user3\" =&gt; { name: \"Bob Wilson\", age: 31, role: \"developer\" },\n  \"user4\" =&gt; { name: \"Carol Davis\", age: 25, role: \"designer\" }\n}\n\n# \u5024\u306b\u57fa\u3065\u304f\u691c\u7d22\ndeveloper = users.find { |id, user| user[:role] == \"developer\" }\nputs developer.inspect  # =&gt; [\"user1\", {:name=&gt;\"John Smith\", :age=&gt;28, :role=&gt;\"developer\"}]\n\n# \u8907\u6570\u306e\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u691c\u7d22\nexperienced_developer = users.find do |id, user| \n  user[:role] == \"developer\" &amp;&amp; user[:age] &gt; 30\nend\nputs experienced_developer.inspect  # =&gt; [\"user3\", {:name=&gt;\"Bob Wilson\", :age=&gt;31, :role=&gt;\"developer\"}]\n\n# \u30ad\u30fc\u3068\u5024\u306e\u4e21\u65b9\u3092\u4f7f\u7528\u3057\u305f\u691c\u7d22\nspecific_user = users.find { |id, user| id.start_with?(\"user\") &amp;&amp; user[:age] &lt; 30 }\nputs specific_user.inspect  # =&gt; [\"user1\", {:name=&gt;\"John Smith\", :age=&gt;28, :role=&gt;\"developer\"}]\n\n# \u540d\u524d\u306e\u90e8\u5206\u4e00\u81f4\u3068\u5e74\u9f62\u306b\u3088\u308b\u691c\u7d22\nname_age_match = users.find { |_, user| user[:name].include?(\"son\") &amp;&amp; user[:age] &gt; 30 }\nputs name_age_match.inspect  # =&gt; [\"user3\", {:name=&gt;\"Bob Wilson\", :age=&gt;31, :role=&gt;\"developer\"}]<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u4f8b\u306f\u3001find\u30e1\u30bd\u30c3\u30c9\u306e\u67d4\u8edf\u6027\u3068\u5f37\u529b\u3055\u3092\u793a\u3057\u3066\u3044\u307e\u3059\u3002\u6761\u4ef6\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u8907\u96d1\u306a\u691c\u7d22\u8981\u4ef6\u306b\u3082\u5bfe\u5fdc\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001find\u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"i-12\">find\u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-13\">\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u3067\u306efind\u30e1\u30bd\u30c3\u30c9\u306e\u52b9\u7387\u7684\u306a\u4f7f\u3044\u65b9<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u3092\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u306b\u5bfe\u3057\u3066\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5\u304c\u91cd\u8981\u3067\u3059\u3002\u4ee5\u4e0b\u306b\u3001\u52b9\u7387\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-14\">\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u306e\u6d3b\u7528<\/h3>\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=\"\"># \u975e\u52b9\u7387\u306a\u5b9f\u88c5\nlarge_array = (1..1000000).to_a\nresult = large_array.find do |num|\n  expensive_calculation(num)\n  num &gt; 100 &amp;&amp; num % 7 == 0\nend\n\n# \u52b9\u7387\u7684\u306a\u5b9f\u88c5\uff1a\u8efd\u3044\u6761\u4ef6\u3092\u5148\u306b\u8a55\u4fa1\nresult = large_array.find do |num|\n  next false unless num &gt; 100  # \u8efd\u3044\u6761\u4ef6\u3092\u5148\u306b\u30c1\u30a7\u30c3\u30af\n  next false unless num % 7 == 0  # \u6b21\u306b\u8efd\u3044\u6761\u4ef6\u3092\u30c1\u30a7\u30c3\u30af\n  expensive_calculation(num)  # \u91cd\u3044\u51e6\u7406\u306f\u6700\u5f8c\u306b\u5b9f\u884c\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-15\">\u30e1\u30e2\u5316\u306e\u6d3b\u7528<\/h3>\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# \u30e1\u30e2\u5316\u3092\u4f7f\u7528\u3057\u306a\u3044\u5834\u5408\ndef expensive_calculation(num)\n  sleep(0.001)  # \u91cd\u3044\u51e6\u7406\u3092\u30b7\u30df\u30e5\u30ec\u30fc\u30c8\n  num * num\nend\n\n# \u30e1\u30e2\u5316\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\n@calculation_cache = {}\ndef memoized_calculation(num)\n  @calculation_cache[num] ||= begin\n    sleep(0.001)  # \u91cd\u3044\u51e6\u7406\u3092\u30b7\u30df\u30e5\u30ec\u30fc\u30c8\n    num * num\n  end\nend\n\nnumbers = (1..100).to_a\n\n# \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u6bd4\u8f03\nBenchmark.bm do |x|\n  x.report(\"Without memoization:\") do\n    numbers.find { |n| expensive_calculation(n) &gt; 5000 }\n  end\n\n  x.report(\"With memoization:\") do\n    numbers.find { |n| memoized_calculation(n) &gt; 5000 }\n  end\nend<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-16\">find_all\u3084select\u3068\u306e\u4f7f\u3044\u5206\u3051\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u3068\u985e\u4f3c\u30e1\u30bd\u30c3\u30c9\u306e\u7279\u5fb4\u3092\u7406\u89e3\u3057\u3001\u9069\u5207\u306b\u4f7f\u3044\u5206\u3051\u308b\u3053\u3068\u3067\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-17\">\u4f7f\u3044\u5206\u3051\u306e\u57fa\u6e96<\/h3>\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=\"\">numbers = (1..1000).to_a\n\n# find\u30e1\u30bd\u30c3\u30c9\uff1a\u6700\u521d\u306e\u4e00\u81f4\u306e\u307f\u304c\u5fc5\u8981\u306a\u5834\u5408\n# \u6761\u4ef6\u306b\u4e00\u81f4\u3057\u305f\u3089\u3059\u3050\u306b\u51e6\u7406\u3092\u7d42\u4e86\nfirst_match = numbers.find { |n| n % 100 == 0 }  # =&gt; 100\n\n# select\u30e1\u30bd\u30c3\u30c9\uff1a\u3059\u3079\u3066\u306e\u4e00\u81f4\u304c\u5fc5\u8981\u306a\u5834\u5408\n# \u914d\u5217\u5168\u4f53\u3092\u8d70\u67fb\nall_matches = numbers.select { |n| n % 100 == 0 }  # =&gt; [100, 200, 300, ...]\n\n# find_all\u30e1\u30bd\u30c3\u30c9\uff1aselect\u306e\u30a8\u30a4\u30ea\u30a2\u30b9\n# select\u3068\u540c\u3058\u52d5\u4f5c\nall_matches_alt = numbers.find_all { |n| n % 100 == 0 }  # =&gt; [100, 200, 300, ...]<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-18\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03<\/h3>\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\nlarge_array = (1..1000000).to_a\n\nBenchmark.bm do |x|\n  x.report(\"find:\") do\n    large_array.find { |n| n % 100000 == 0 }\n  end\n\n  x.report(\"select:\") do\n    large_array.select { |n| n % 100000 == 0 }\n  end\n\n  x.report(\"find_all:\") do\n    large_array.find_all { |n| n % 100000 == 0 }\n  end\nend\n\n# \u7d50\u679c\u4f8b\uff1a\n# find:      0.001s\n# select:    0.150s\n# find_all:  0.150s<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-19\">\u30e1\u30bd\u30c3\u30c9\u306e\u9078\u629e\u30ac\u30a4\u30c9\u30e9\u30a4\u30f3<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6700\u521d\u306e\u4e00\u81f4\u306e\u307f\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1a<code>find<\/code>\u3092\u4f7f\u7528<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u306b\u3088\u308b\u52b9\u7387\u7684\u306a\u5b9f\u884c<\/li>\n\n\n\n<li>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u304c\u5c11\u306a\u3044<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u3059\u3079\u3066\u306e\u4e00\u81f4\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1a<code>select<\/code>\u307e\u305f\u306f<code>find_all<\/code>\u3092\u4f7f\u7528<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5168\u8981\u7d20\u306e\u8d70\u67fb\u304c\u5fc5\u8981<\/li>\n\n\n\n<li>\u7d50\u679c\u3092\u914d\u5217\u3068\u3057\u3066\u4fdd\u6301<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6761\u4ef6\u304c\u8907\u96d1\u306a\u5834\u5408\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8efd\u3044\u6761\u4ef6\u3092\u5148\u306b\u8a55\u4fa1<\/li>\n\n\n\n<li>\u30e1\u30e2\u5316\u3092\u6d3b\u7528<\/li>\n\n\n\n<li>\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u4f7f\u7528<\/li>\n<\/ul>\n\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\u3001find\u30e1\u30bd\u30c3\u30c9\u306e\u52b9\u7387\u7684\u306a\u4f7f\u7528\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"i-20\">\u5b9f\u52d9\u3067\u4f7f\u3048\u308bfind\u30e1\u30bd\u30c3\u30c9\u306e\u5fdc\u7528\u4f8b<\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-21\">ActiveRecord\u3068\u7d44\u307f\u5408\u308f\u305b\u305f\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u691c\u7d22<\/h2>\n\n\n\n<p>ActiveRecord\u3067\u306f\u3001find\u30e1\u30bd\u30c3\u30c9\u304c\u3055\u3089\u306b\u5f37\u529b\u306a\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u307e\u3059\u3002\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u30ec\u30d9\u30eb\u3067\u306e\u6700\u9069\u5316\u3068\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u306a\u691c\u7d22\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-22\">\u57fa\u672c\u7684\u306aActiveRecord\u306efind<\/h3>\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=\"\"># \u30e2\u30c7\u30eb\u306e\u5b9a\u7fa9\nclass User &lt; ApplicationRecord\n  has_many :posts\n  has_many :comments\nend\n\n# ID\u306b\u3088\u308b\u691c\u7d22\uff08\u6700\u3082\u57fa\u672c\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\uff09\nuser = User.find(1)  # SELECT * FROM users WHERE id = 1 LIMIT 1\n\n# \u8907\u6570\u306eID\u306b\u3088\u308b\u691c\u7d22\nusers = User.find([1, 2, 3])  # SELECT * FROM users WHERE id IN (1, 2, 3)\n\n# find_by\u3092\u4f7f\u7528\u3057\u305f\u5c5e\u6027\u306b\u3088\u308b\u691c\u7d22\nuser = User.find_by(email: \"example@example.com\")<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-23\">\u95a2\u9023\u4ed8\u3051\u3092\u4f7f\u7528\u3057\u305f\u9ad8\u5ea6\u306a\u691c\u7d22<\/h3>\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 Post &lt; ApplicationRecord\n  belongs_to :user\n  has_many :comments\n\n  # \u30b9\u30b3\u30fc\u30d7\u306e\u5b9a\u7fa9\n  scope :published, -&gt; { where(published: true) }\n  scope :recent, -&gt; { where('created_at &gt; ?', 1.week.ago) }\nend\n\n# \u95a2\u9023\u4ed8\u3051\u3092\u4f7f\u7528\u3057\u305f\u691c\u7d22\nuser = User.find_by(email: \"example@example.com\")\nrecent_post = user.posts.find { |post| post.comments.count &gt; 5 }\n\n# \u3088\u308a\u52b9\u7387\u7684\u306a\u5b9f\u88c5\uff08N+1\u554f\u984c\u3092\u56de\u907f\uff09\nrecent_post = user.posts\n  .includes(:comments)\n  .find { |post| post.comments.count &gt; 5 }<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-24\">\u8907\u96d1\u306a\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u9ad8\u5ea6\u306a\u691c\u7d22\u306e\u5b9f\u88c5\u65b9\u6cd5<\/h2>\n\n\n\n<p>\u5b9f\u52d9\u3067\u306f\u3001\u8907\u6570\u306e\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u8907\u96d1\u306a\u691c\u7d22\u304c\u5fc5\u8981\u306b\u306a\u308b\u3053\u3068\u304c\u3088\u304f\u3042\u308a\u307e\u3059\u3002\u4ee5\u4e0b\u306b\u3001\u5b9f\u8df5\u7684\u306a\u5b9f\u88c5\u4f8b\u3092\u793a\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-25\">\u30ab\u30b9\u30bf\u30e0\u30d5\u30a1\u30a4\u30f3\u30c0\u30fc\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5<\/h3>\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 Order &lt; ApplicationRecord\n  belongs_to :user\n  has_many :order_items\n\n  def self.find_pending_high_value\n    where(status: 'pending').find { |order| order.total_amount &gt; 10000 }\n  end\n\n  def self.find_eligible_for_discount\n    includes(:user, :order_items).find do |order|\n      order.user.premium? &amp;&amp; \n      order.order_items.sum(&amp;:quantity) &gt; 5 &amp;&amp;\n      order.created_at &gt; 30.days.ago\n    end\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-26\">\u8907\u96d1\u306a\u691c\u7d22\u6761\u4ef6\u306e\u5b9f\u88c5<\/h3>\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 Product &lt; ApplicationRecord\n  has_many :stock_items\n  has_many :reviews\n\n  # \u5728\u5eab\u304c\u3042\u308a\u3001\u9ad8\u8a55\u4fa1\u306e\u5546\u54c1\u3092\u691c\u7d22\n  def self.find_featured_product\n    includes(:stock_items, :reviews).find do |product|\n      product.stock_items.any? { |item| item.quantity &gt; 0 } &amp;&amp;\n      product.reviews.count &gt;= 10 &amp;&amp;\n      product.reviews.average(&amp;:rating) &gt;= 4.5\n    end\n  end\nend\n\n# \u4f7f\u7528\u4f8b\nfeatured_product = Product.find_featured_product<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-27\">\u6761\u4ef6\u5206\u5c90\u3092\u542b\u3080\u52d5\u7684\u306a\u691c\u7d22<\/h3>\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 Employee &lt; ApplicationRecord\n  belongs_to :department\n  has_many :skills\n\n  def self.find_suitable_candidate(required_skills, department_id = nil)\n    candidates = includes(:skills, :department)\n\n    candidates.find do |employee|\n      # \u30b9\u30ad\u30eb\u306e\u6761\u4ef6\u30c1\u30a7\u30c3\u30af\n      has_required_skills = required_skills.all? do |skill|\n        employee.skills.any? { |s| s.name == skill }\n      end\n\n      # \u90e8\u9580\u306e\u6761\u4ef6\u30c1\u30a7\u30c3\u30af\uff08\u6307\u5b9a\u304c\u3042\u308b\u5834\u5408\uff09\n      department_match = department_id.nil? || \n                        employee.department_id == department_id\n\n      # availability\uff08\u7a3c\u50cd\u72b6\u6cc1\uff09\u306e\u30c1\u30a7\u30c3\u30af\n      is_available = employee.available_for_project?\n\n      has_required_skills &amp;&amp; department_match &amp;&amp; is_available\n    end\n  end\n\n  def available_for_project?\n    # \u7a3c\u50cd\u72b6\u6cc1\u3092\u78ba\u8a8d\u3059\u308b\u30ed\u30b8\u30c3\u30af\n    current_projects.count &lt; 3 &amp;&amp; !on_leave?\n  end\nend<\/pre>\n\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001ActiveRecord\u3068find\u30e1\u30bd\u30c3\u30c9\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u8907\u96d1\u306a\u30d3\u30b8\u30cd\u30b9\u30ed\u30b8\u30c3\u30af\u3092\u542b\u3080\u691c\u7d22\u3092\u5b9f\u88c5\u3067\u304d\u307e\u3059\u3002\u305f\u3060\u3057\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u3066\u3001\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u4f5c\u6210\u3084\u3001\u30af\u30a8\u30ea\u306e\u6700\u9069\u5316\u3092\u884c\u3046\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"i-28\">find\u30e1\u30bd\u30c3\u30c9\u306e\u3088\u304f\u3042\u308b\u30a8\u30e9\u30fc\u3068\u5bfe\u51e6\u6cd5<\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-29\">nil\u30a8\u30e9\u30fc\u306e\u539f\u56e0\u3068\u9069\u5207\u306a\u51e6\u7406\u4f8b\u5916\u306e\u5b9f\u88c5<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u969b\u306b\u3088\u304f\u906d\u9047\u3059\u308b\u306e\u304c\u3001nil\u306b\u95a2\u9023\u3059\u308b\u30a8\u30e9\u30fc\u3067\u3059\u3002\u3053\u308c\u3089\u306e\u30a8\u30e9\u30fc\u3092\u9069\u5207\u306b\u51e6\u7406\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5805\u7262\u306a\u30b3\u30fc\u30c9\u3092\u5b9f\u88c5\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-30\">\u3088\u304f\u3042\u308bnil\u30a8\u30e9\u30fc\u306e\u30d1\u30bf\u30fc\u30f3<\/h3>\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=\"\"># 1. \u5b58\u5728\u3057\u306a\u3044\u8981\u7d20\u3078\u306e\u30e1\u30bd\u30c3\u30c9\u547c\u3073\u51fa\u3057\nnumbers = [1, 2, 3, 4, 5]\nresult = numbers.find { |n| n &gt; 10 }\nresult.positive?  # =&gt; NoMethodError: undefined method `positive?' for nil:NilClass\n\n# 2. nil\u30ac\u30fc\u30c9\u6f14\u7b97\u5b50\u3092\u4f7f\u7528\u3057\u305f\u5b89\u5168\u306a\u5b9f\u88c5\nresult = numbers.find { |n| n &gt; 10 }&amp;.positive?  # =&gt; nil\n\n# 3. \u6761\u4ef6\u5206\u5c90\u306b\u3088\u308b\u9069\u5207\u306a\u51e6\u7406\nresult = numbers.find { |n| n &gt; 10 }\nif result\n  puts \"Found: #{result}\"\nelse\n  puts \"No matching element found\"\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-31\">\u4f8b\u5916\u51e6\u7406\u306e\u5b9f\u88c5<\/h3>\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=\"\">def find_user_by_email(email)\n  users = [\n    { email: \"user1@example.com\", name: \"User 1\" },\n    { email: \"user2@example.com\", name: \"User 2\" }\n  ]\n\n  result = users.find { |user| user[:email] == email }\n\n  # \u30ab\u30b9\u30bf\u30e0\u4f8b\u5916\u306e\u5b9a\u7fa9\n  class UserNotFoundError &lt; StandardError; end\n\n  # \u4f8b\u5916\u51e6\u7406\u306e\u5b9f\u88c5\n  raise UserNotFoundError, \"User with email #{email} not found\" if result.nil?\n\n  result\nrescue UserNotFoundError =&gt; e\n  puts \"Error: #{e.message}\"\n  nil\nend\n\n# \u4f7f\u7528\u4f8b\nuser = find_user_by_email(\"nonexistent@example.com\")<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-32\">\u30d6\u30ed\u30c3\u30af\u4f7f\u7528\u6642\u306e\u6ce8\u610f\u70b9\u3068\u30c7\u30d0\u30c3\u30b0\u306e\u30b3\u30c4<\/h2>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u3067\u30d6\u30ed\u30c3\u30af\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u4e00\u822c\u7684\u306a\u554f\u984c\u3068\u3001\u305d\u308c\u3089\u3092\u56de\u907f\u3059\u308b\u305f\u3081\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-33\">\u30d6\u30ed\u30c3\u30af\u306e\u623b\u308a\u5024\u306b\u95a2\u3059\u308b\u6ce8\u610f\u70b9<\/h3>\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=\"\"># 1. \u610f\u56f3\u3057\u306a\u3044\u623b\u308a\u5024\nnumbers = [1, 2, 3, 4, 5]\n\n# \u554f\u984c\u306e\u3042\u308b\u30b3\u30fc\u30c9\nresult = numbers.find do |n|\n  puts \"Checking #{n}\"  # \u3053\u306eputs\u304c\u6700\u5f8c\u306e\u5f0f\u306b\u306a\u3063\u3066\u3057\u307e\u3046\n  n &gt; 3\nend\n\n# \u4fee\u6b63\u3057\u305f\u30b3\u30fc\u30c9\nresult = numbers.find do |n|\n  puts \"Checking #{n}\"  # \u30c7\u30d0\u30c3\u30b0\u51fa\u529b\n  n &gt; 3  # \u660e\u793a\u7684\u306b\u6761\u4ef6\u3092\u6700\u5f8c\u306e\u5f0f\u306b\u3059\u308b\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-34\">\u30c7\u30d0\u30c3\u30b0\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\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=\"\">def debug_find(collection)\n  collection.find do |element|\n    # \u30c7\u30d0\u30c3\u30b0\u60c5\u5831\u306e\u51fa\u529b\n    puts \"Currently checking: #{element.inspect}\"\n\n    begin\n      result = yield(element)\n      puts \"Result for #{element}: #{result}\"\n      result\n    rescue =&gt; e\n      puts \"Error occurred while processing #{element}: #{e.message}\"\n      false\n    end\n  end\nend\n\n# \u4f7f\u7528\u4f8b\nnumbers = [1, 2, \"3\", 4, 5]\nresult = debug_find(numbers) do |n|\n  # \u610f\u56f3\u7684\u306b\u30a8\u30e9\u30fc\u3092\u8d77\u3053\u3059\u6761\u4ef6\n  n.to_i &gt; 3\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-35\">\u3088\u304f\u3042\u308b\u843d\u3068\u3057\u7a74\u3068\u305d\u306e\u5bfe\u7b56<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u8907\u96d1\u306a\u6761\u4ef6\u306e\u30c7\u30d0\u30c3\u30b0<\/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 Product\n  attr_reader :name, :price, :stock\n\n  def self.debug_complex_find(products, min_price, min_stock)\n    products.find do |product|\n      puts \"\\nChecking product: #{product.name}\"\n\n      price_check = product.price &gt;= min_price\n      puts \"Price check (&gt;= #{min_price}): #{price_check}\"\n\n      stock_check = product.stock &gt;= min_stock\n      puts \"Stock check (&gt;= #{min_stock}): #{stock_check}\"\n\n      price_check &amp;&amp; stock_check\n    end\n  end\nend\n\n# \u30c7\u30d0\u30c3\u30b0\u5b9f\u884c\u4f8b\nproducts = [\n  Product.new(\"A\", 100, 5),\n  Product.new(\"B\", 200, 3),\n  Product.new(\"C\", 300, 10)\n]\n\nProduct.debug_complex_find(products, 250, 8)<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u30c7\u30d0\u30c3\u30b0<\/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=\"\">require 'benchmark'\n\ndef performance_debug_find(collection)\n  times = []\n  result = collection.find do |element|\n    start_time = Time.now\n\n    matched = yield(element)\n\n    end_time = Time.now\n    duration = end_time - start_time\n    times &lt;&lt; { element: element, duration: duration }\n\n    matched\n  end\n\n  # \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u60c5\u5831\u306e\u51fa\u529b\n  puts \"\\nPerformance Analysis:\"\n  times.each do |t|\n    puts \"Element: #{t[:element]}, Time: #{t[:duration]}s\"\n  end\n\n  result\nend<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30c7\u30d0\u30c3\u30b0\u30c6\u30af\u30cb\u30c3\u30af\u3068\u30a8\u30e9\u30fc\u51e6\u7406\u30d1\u30bf\u30fc\u30f3\u3092\u9069\u5207\u306b\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u5b9f\u88c5\u3067\u304d\u307e\u3059\u3002\u307e\u305f\u3001\u554f\u984c\u304c\u767a\u751f\u3057\u305f\u969b\u306e\u539f\u56e0\u7279\u5b9a\u3082\u5bb9\u6613\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"i-36\">Ruby\u306efind\u30e1\u30bd\u30c3\u30c9\u5b8c\u5168\u30de\u30b9\u30bf\u30fc\u8b1b\u5ea7\u306e\u307e\u3068\u3081<\/h1>\n\n\n\n<p>\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001Ruby\u306efind\u30e1\u30bd\u30c3\u30c9\u306b\u3064\u3044\u3066\u4ee5\u4e0b\u306e\u5185\u5bb9\u3092\u8a73\u3057\u304f\u89e3\u8aac\u3057\u307e\u3057\u305f\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>find\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3068\u7279\u5fb4<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u57fa\u672c\u69cb\u6587\u3068\u623b\u308a\u5024\u306e\u7279\u5fb4<\/li>\n\n\n\n<li>\u914d\u5217\u3068Enumerable\u3067\u306e\u4f7f\u7528\u65b9\u6cd5\u306e\u9055\u3044<\/li>\n\n\n\n<li>\u5b9f\u7528\u7684\u306a\u30b3\u30fc\u30c9\u4f8b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u65b9\u6cd5<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6570\u5024\u3001\u6587\u5b57\u5217\u3001\u30cf\u30c3\u30b7\u30e5\u3067\u306e\u691c\u7d22\u5b9f\u88c5<\/li>\n\n\n\n<li>\u8907\u96d1\u306a\u6761\u4ef6\u3067\u306e\u691c\u7d22\u65b9\u6cd5<\/li>\n\n\n\n<li>\u69d8\u3005\u306a\u30c7\u30fc\u30bf\u578b\u3067\u306e\u6d3b\u7528\u4f8b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u30c6\u30af\u30cb\u30c3\u30af<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u3067\u306e\u52b9\u7387\u7684\u306a\u4f7f\u7528\u65b9\u6cd5<\/li>\n\n\n\n<li>\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u3068\u30e1\u30e2\u5316\u306e\u6d3b\u7528<\/li>\n\n\n\n<li>\u985e\u4f3c\u30e1\u30bd\u30c3\u30c9\u3068\u306e\u4f7f\u3044\u5206\u3051<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5b9f\u52d9\u3067\u306e\u5fdc\u7528\u4f8b<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>ActiveRecord\u3068\u306e\u7d44\u307f\u5408\u308f\u305b<\/li>\n\n\n\n<li>\u8907\u96d1\u306a\u6761\u4ef6\u3067\u306e\u691c\u7d22\u5b9f\u88c5<\/li>\n\n\n\n<li>\u5b9f\u8df5\u7684\u306a\u30e6\u30fc\u30b9\u30b1\u30fc\u30b9<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u3068\u30c7\u30d0\u30c3\u30b0<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u3088\u304f\u3042\u308b\u30a8\u30e9\u30fc\u3068\u305d\u306e\u5bfe\u51e6\u6cd5<\/li>\n\n\n\n<li>\u52b9\u679c\u7684\u306a\u30c7\u30d0\u30c3\u30b0\u65b9\u6cd5<\/li>\n\n\n\n<li>\u5805\u7262\u306a\u30b3\u30fc\u30c9\u306e\u5b9f\u88c5\u65b9\u6cd5<\/li>\n<\/ul>\n\n\n\n<p>find\u30e1\u30bd\u30c3\u30c9\u306f\u3001Ruby\u306e\u5f37\u529b\u306a\u691c\u7d22\u6a5f\u80fd\u3092\u63d0\u4f9b\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u306e1\u3064\u3067\u3059\u3002\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3092\u30de\u30b9\u30bf\u30fc\u3057\u3001\u9069\u5207\u306a\u6700\u9069\u5316\u3068\u30a8\u30e9\u30fc\u51e6\u7406\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u3053\u306e\u8a18\u4e8b\u3067\u5b66\u3093\u3060\u5185\u5bb9\u3092\u6d3b\u304b\u3057\u3066\u3001\u305c\u3072\u5b9f\u969b\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067find\u30e1\u30bd\u30c3\u30c9\u3092\u6d3b\u7528\u3057\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ruby \u306efind\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f \u57fa\u790e\u304b\u3089\u89e3\u8aac Warning: Undefined array key &#8220;is_admin&#8221; in \/home\/xs392991\/dexall.co.jp\/public_html\/ar &#8230; <\/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-1286","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\/1286","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=1286"}],"version-history":[{"count":1,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1286\/revisions"}],"predecessor-version":[{"id":1288,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1286\/revisions\/1288"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1286"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1286"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1286"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}