{"id":233,"date":"2026-03-09T22:12:54","date_gmt":"2026-03-09T14:12:54","guid":{"rendered":"https:\/\/www.resilence.cn\/?p=233"},"modified":"2026-03-09T22:12:54","modified_gmt":"2026-03-09T14:12:54","slug":"day-7-%e6%95%b0%e7%bb%84%e5%92%8c%e5%be%aa%e7%8e%af","status":"publish","type":"post","link":"https:\/\/www.resilence.cn\/?p=233","title":{"rendered":"Day-7-\u6570\u7ec4\u548c\u5faa\u73af"},"content":{"rendered":"<h1>Day 7: \u6570\u7ec4\u548c\u5faa\u73af<\/h1>\n<h2>\ud83c\udfaf \u5b66\u4e60\u76ee\u6807<\/h2>\n<ul>\n<li>\u7406\u89e3\u6570\u7ec4\u7684\u6982\u5ff5\u548c\u7528\u9014<\/li>\n<li>\u638c\u63e1 for \u5faa\u73af\u548c while \u5faa\u73af\u7684\u4f7f\u7528<\/li>\n<li>\u5b66\u4f1a\u7528\u6570\u7ec4\u5b58\u50a8\u548c\u64cd\u4f5c\u591a\u4e2a\u6570\u636e<\/li>\n<\/ul>\n<h2>\ud83d\udca1 \u6838\u5fc3\u6982\u5ff5<\/h2>\n<h3>\u4ec0\u4e48\u662f\u6570\u7ec4\uff1f<\/h3>\n<p>\u6570\u7ec4\u662f\u4e00\u79cd\u53ef\u4ee5\u5b58\u50a8\u591a\u4e2a\u503c\u7684\u53d8\u91cf\u3002\u60f3\u8c61\u4e00\u4e0b\uff1a<\/p>\n<ul>\n<li><strong>\u53d8\u91cf<\/strong> = \u4e00\u4e2a\u76d2\u5b50\uff0c\u53ea\u80fd\u653e\u4e00\u4e2a\u4e1c\u897f<\/li>\n<li><strong>\u6570\u7ec4<\/strong> = \u4e00\u6392\u6709\u7f16\u53f7\u7684\u76d2\u5b50\uff0c\u53ef\u4ee5\u653e\u591a\u4e2a\u4e1c\u897f<\/li>\n<\/ul>\n<pre><code class=\"language-javascript\">\/\/ \u53d8\u91cf - \u53ea\u80fd\u5b58\u4e00\u4e2a\u540d\u5b57\nlet name = &quot;\u5f20\u4e09&quot;;\n\n\/\/ \u6570\u7ec4 - \u53ef\u4ee5\u5b58\u591a\u4e2a\u540d\u5b57\nlet names = [&quot;\u5f20\u4e09&quot;, &quot;\u674e\u56db&quot;, &quot;\u738b\u4e94&quot;];\n<\/code><\/pre>\n<h3>\u4e3a\u4ec0\u4e48\u9700\u8981\u6570\u7ec4\uff1f<\/h3>\n<ul>\n<li><strong>\u6279\u91cf\u5904\u7406<\/strong>: \u4e00\u6b21\u6027\u5b58\u50a8\u548c\u64cd\u4f5c\u591a\u4e2a\u76f8\u5173\u6570\u636e<\/li>\n<li><strong>\u7b80\u5316\u4ee3\u7801<\/strong>: \u907f\u514d\u521b\u5efa\u5927\u91cf\u91cd\u590d\u7684\u53d8\u91cf<\/li>\n<li><strong>\u6570\u636e\u7ed3\u6784<\/strong>: \u662f\u5176\u4ed6\u590d\u6742\u6570\u636e\u7ed3\u6784\u7684\u57fa\u7840<\/li>\n<\/ul>\n<h3>\u4ec0\u4e48\u662f\u5faa\u73af\uff1f<\/h3>\n<p>\u5faa\u73af\u662f\u91cd\u590d\u6267\u884c\u4ee3\u7801\u7684\u7ed3\u6784\u3002\u5f53\u9700\u8981\uff1a<\/p>\n<ul>\n<li>\u904d\u5386\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20<\/li>\n<li>\u91cd\u590d\u6267\u884c\u67d0\u6bb5\u4ee3\u7801\u591a\u6b21<\/li>\n<li>\u5904\u7406\u7c7b\u4f3c\u7684\u6570\u636e<\/li>\n<\/ul>\n<h2>\ud83d\udcdd \u57fa\u672c\u8bed\u6cd5<\/h2>\n<h3>\u6570\u7ec4\u7684\u521b\u5efa\u548c\u8bbf\u95ee<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u521b\u5efa\u6570\u7ec4\nlet fruits = [&quot;\u82f9\u679c&quot;, &quot;\u9999\u8549&quot;, &quot;\u6a59\u5b50&quot;];\nlet numbers = [1, 2, 3, 4, 5];\nlet mixed = [&quot;\u6587\u5b57&quot;, 123, true, null];\n\n\/\/ \u8bbf\u95ee\u6570\u7ec4\u5143\u7d20\uff08\u7d22\u5f15\u4ece 0 \u5f00\u59cb\uff09\nconsole.log(fruits[0]);  \/\/ &quot;\u82f9\u679c&quot; - \u7b2c\u4e00\u4e2a\u5143\u7d20\nconsole.log(fruits[1]);  \/\/ &quot;\u9999\u8549&quot; - \u7b2c\u4e8c\u4e2a\u5143\u7d20\nconsole.log(fruits[2]);  \/\/ &quot;\u6a59\u5b50&quot; - \u7b2c\u4e09\u4e2a\u5143\u7d20\n\n\/\/ \u4fee\u6539\u6570\u7ec4\u5143\u7d20\nfruits[0] = &quot;\u8461\u8404&quot;;\nconsole.log(fruits);  \/\/ [&quot;\u8461\u8404&quot;, &quot;\u9999\u8549&quot;, &quot;\u6a59\u5b50&quot;]\n\n\/\/ \u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\nconsole.log(fruits.length);  \/\/ 3\n<\/code><\/pre>\n<h3>for \u5faa\u73af<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u57fa\u672c\u8bed\u6cd5\nfor (\u521d\u59cb\u5316; \u6761\u4ef6; \u66f4\u65b0) {\n    \/\/ \u5faa\u73af\u4f53 - \u8981\u91cd\u590d\u6267\u884c\u7684\u4ee3\u7801\n}\n\n\/\/ \u793a\u4f8b 1: \u6253\u5370\u6570\u5b57 1-5\nfor (let i = 1; i &lt;= 5; i++) {\n    console.log(i);\n}\n\/\/ \u8f93\u51fa: 1, 2, 3, 4, 5\n\n\/\/ \u793a\u4f8b 2: \u904d\u5386\u6570\u7ec4\nlet colors = [&quot;\u7ea2&quot;, &quot;\u9ec4&quot;, &quot;\u84dd&quot;];\nfor (let i = 0; i &lt; colors.length; i++) {\n    console.log(`\u989c\u8272 ${i}: ${colors[i]}`);\n}\n\/\/ \u8f93\u51fa: \u989c\u8272 0: \u7ea2, \u989c\u8272 1: \u9ec4, \u989c\u8272 2: \u84dd\n<\/code><\/pre>\n<h3>while \u5faa\u73af<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u57fa\u672c\u8bed\u6cd5\nwhile (\u6761\u4ef6) {\n    \/\/ \u5faa\u73af\u4f53\n}\n\n\/\/ \u793a\u4f8b: \u5012\u8ba1\u65f6\nlet countdown = 5;\nwhile (countdown &gt; 0) {\n    console.log(countdown);\n    countdown--;\n}\n\/\/ \u8f93\u51fa: 5, 4, 3, 2, 1\n<\/code><\/pre>\n<h3>for&#8230;of \u5faa\u73af\uff08\u904d\u5386\u6570\u7ec4\uff09<\/h3>\n<pre><code class=\"language-javascript\">let animals = [&quot;\u732b&quot;, &quot;\u72d7&quot;, &quot;\u9e1f&quot;];\n\nfor (let animal of animals) {\n    console.log(&quot;\u52a8\u7269: &quot; + animal);\n}\n\/\/ \u8f93\u51fa: \u52a8\u7269: \u732b, \u52a8\u7269: \u72d7, \u52a8\u7269: \u9e1f\n<\/code><\/pre>\n<h2>\ud83c\udfae \u793a\u4f8b\u4ee3\u7801<\/h2>\n<h3>\u793a\u4f8b 1: \u8ba1\u7b97\u6570\u7ec4\u4e2d\u6570\u5b57\u7684\u603b\u548c<\/h3>\n<pre><code class=\"language-javascript\">let scores = [85, 92, 78, 95, 88];\nlet sum = 0;\n\n\/\/ \u4f7f\u7528 for \u5faa\u73af\u6c42\u548c\nfor (let i = 0; i &lt; scores.length; i++) {\n    sum += scores[i];\n    console.log(`\u7b2c ${i+1} \u95e8\u8bfe\u6210\u7ee9: ${scores[i]}`);\n}\n\nconsole.log(&quot;\u603b\u5206: &quot; + sum);\nconsole.log(&quot;\u5e73\u5747\u5206: &quot; + (sum \/ scores.length));\n<\/code><\/pre>\n<p><strong>\u8f93\u51fa:<\/strong><\/p>\n<pre><code>\u7b2c 1 \u95e8\u8bfe\u6210\u7ee9: 85\n\u7b2c 2 \u95e8\u8bfe\u6210\u7ee9: 92\n\u7b2c 3 \u95e8\u8bfe\u6210\u7ee9: 78\n\u7b2c 4 \u95e8\u8bfe\u6210\u7ee9: 95\n\u7b2c 5 \u95e8\u8bfe\u6210\u7ee9: 88\n\u603b\u5206: 438\n\u5e73\u5747\u5206: 87.6\n<\/code><\/pre>\n<h3>\u793a\u4f8b 2: \u627e\u51fa\u6570\u7ec4\u4e2d\u7684\u6700\u5927\u503c<\/h3>\n<pre><code class=\"language-javascript\">let numbers = [23, 45, 12, 67, 34, 89, 5];\nlet max = numbers[0];  \/\/ \u5047\u8bbe\u7b2c\u4e00\u4e2a\u662f\u6700\u5927\u7684\n\nfor (let i = 1; i &lt; numbers.length; i++) {\n    if (numbers[i] &gt; max) {\n        max = numbers[i];\n        console.log(`\u53d1\u73b0\u66f4\u5927\u7684\u6570\u5b57: ${numbers[i]}`);\n    }\n}\n\nconsole.log(&quot;\u6700\u5927\u503c\u662f: &quot; + max);\n<\/code><\/pre>\n<h3>\u793a\u4f8b 3: \u7b5b\u9009\u6570\u7ec4\u4e2d\u7684\u5076\u6570<\/h3>\n<pre><code class=\"language-javascript\">let allNumbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];\nlet evenNumbers = [];\n\nfor (let num of allNumbers) {\n    if (num % 2 === 0) {  \/\/ \u5224\u65ad\u662f\u5426\u662f\u5076\u6570\n        evenNumbers.push(num);\n    }\n}\n\nconsole.log(&quot;\u6240\u6709\u6570\u5b57: &quot; + allNumbers);\nconsole.log(&quot;\u5076\u6570: &quot; + evenNumbers);\n<\/code><\/pre>\n<h3>\u793a\u4f8b 4: \u521b\u5efa\u4e00\u4e2a\u5f85\u529e\u4e8b\u9879\u5217\u8868<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u521d\u59cb\u5f85\u529e\u5217\u8868\nlet todos = [&quot;\u5199\u4f5c\u4e1a&quot;, &quot;\u4e70\u83dc&quot;, &quot;\u6253\u626b\u623f\u95f4&quot;];\n\n\/\/ \u6dfb\u52a0\u65b0\u4efb\u52a1\ntodos.push(&quot;\u953b\u70bc\u8eab\u4f53&quot;);\ntodos.push(&quot;\u9605\u8bfb 30 \u5206\u949f&quot;);\n\nconsole.log(&quot;=== \u6211\u7684\u5f85\u529e\u4e8b\u9879 ===&quot;);\n\n\/\/ \u663e\u793a\u6240\u6709\u4efb\u52a1\nfor (let i = 0; i &lt; todos.length; i++) {\n    console.log(`${i + 1}. ${todos[i]}`);\n}\n\n\/\/ \u6807\u8bb0\u5b8c\u6210\nconsole.log(&quot;\\n\u5b8c\u6210\u7b2c 2 \u4e2a\u4efb\u52a1: &quot; + todos[1]);\ntodos.splice(1, 1);  \/\/ \u5220\u9664\u7b2c 2 \u4e2a\u4efb\u52a1\n\nconsole.log(&quot;\\n=== \u66f4\u65b0\u540e\u7684\u5f85\u529e\u4e8b\u9879 ===&quot;);\nfor (let todo of todos) {\n    console.log(&quot;\u2022 &quot; + todo);\n}\n<\/code><\/pre>\n<p><strong>\u8f93\u51fa:<\/strong><\/p>\n<pre><code>=== \u6211\u7684\u5f85\u529e\u4e8b\u9879 ===\n1. \u5199\u4f5c\u4e1a\n2. \u4e70\u83dc\n3. \u6253\u626b\u623f\u95f4\n4. \u953b\u70bc\u8eab\u4f53\n5. \u9605\u8bfb 30 \u5206\u949f\n\n\u5b8c\u6210\u7b2c 2 \u4e2a\u4efb\u52a1: \u4e70\u83dc\n\n=== \u66f4\u65b0\u540e\u7684\u5f85\u529e\u4e8b\u9879 ===\n\u2022 \u5199\u4f5c\u4e1a\n\u2022 \u6253\u626b\u623f\u95f4\n\u2022 \u953b\u70bc\u8eab\u4f53\n\u2022 \u9605\u8bfb 30 \u5206\u949f\n<\/code><\/pre>\n<h3>\u793a\u4f8b 5: \u5d4c\u5957\u5faa\u73af\uff08\u4e58\u6cd5\u8868\uff09<\/h3>\n<pre><code class=\"language-javascript\">console.log(&quot;=== 9x9 \u4e58\u6cd5\u8868 ===&quot;);\n\nfor (let i = 1; i &lt;= 9; i++) {\n    let line = &quot;&quot;;\n    for (let j = 1; j &lt;= i; j++) {\n        line += `${j}\u00d7${i}=${i*j} `;\n    }\n    console.log(line);\n}\n<\/code><\/pre>\n<p><strong>\u8f93\u51fa:<\/strong><\/p>\n<pre><code>=== 9x9 \u4e58\u6cd5\u8868 ===\n1\u00d71=1 \n1\u00d72=2 2\u00d72=4 \n1\u00d73=3 2\u00d73=6 3\u00d73=9 \n1\u00d74=4 2\u00d74=8 3\u00d74=12 4\u00d74=16 \n1\u00d75=5 2\u00d75=10 3\u00d75=15 4\u00d75=20 5\u00d75=25 \n1\u00d76=6 2\u00d76=12 3\u00d76=18 4\u00d76=24 5\u00d76=30 6\u00d76=36 \n1\u00d77=7 2\u00d77=14 3\u00d77=21 4\u00d77=28 5\u00d77=35 6\u00d77=42 7\u00d77=49 \n1\u00d78=8 2\u00d78=16 3\u00d78=24 4\u00d78=32 5\u00d78=40 6\u00d78=48 7\u00d78=56 8\u00d78=64 \n1\u00d79=9 2\u00d79=18 3\u00d79=27 4\u00d79=36 5\u00d79=45 6\u00d79=54 7\u00d79=63 8\u00d79=72 9\u00d79=81 \n<\/code><\/pre>\n<h2>\u270d\ufe0f \u7ec3\u4e60\u4efb\u52a1<\/h2>\n<h3>\u7ec3\u4e60 1: \u57fa\u7840\u7ec3\u4e60<\/h3>\n<p><strong>\u4efb\u52a1<\/strong>: \u521b\u5efa\u4e00\u4e2a\u5b58\u50a8\u4e00\u5468\u6e29\u5ea6\u7684\u6570\u7ec4<\/p>\n<p><strong>\u8981\u6c42<\/strong>:<\/p>\n<ol>\n<li>\u5b9a\u4e49\u6570\u7ec4 <code>temperatures = [23, 25, 22, 26, 28, 30, 29]<\/code><\/li>\n<li>\u7528\u5faa\u73af\u6253\u5370\u6bcf\u5929\u7684\u6c14\u6e29<\/li>\n<li>\u8ba1\u7b97\u4e00\u5468\u5e73\u5747\u6e29\u5ea6<\/li>\n<li>\u627e\u51fa\u6700\u9ad8\u6e29\u5ea6\u548c\u6700\u4f4e\u6e29\u5ea6<\/li>\n<\/ol>\n<p><strong>\u63d0\u793a<\/strong>:<\/p>\n<ul>\n<li>\u4f7f\u7528 <code>for<\/code> \u5faa\u73af\u904d\u5386\u6570\u7ec4<\/li>\n<li>\u7528\u53d8\u91cf\u4fdd\u5b58\u6700\u5927\u503c\u548c\u6700\u5c0f\u503c<\/li>\n<li>\u5e73\u5747\u6e29\u5ea6 = \u603b\u548c \/ \u6570\u91cf<\/li>\n<\/ul>\n<h3>\u7ec3\u4e60 2: \u8fdb\u9636\u7ec3\u4e60<\/h3>\n<p><strong>\u4efb\u52a1<\/strong>: \u5b9e\u73b0\u4e00\u4e2a\u7b80\u5355\u7684\u8d2d\u7269\u8f66<\/p>\n<p><strong>\u573a\u666f<\/strong>:<\/p>\n<pre><code class=\"language-javascript\">let products = [\n    {name: &quot;\u82f9\u679c&quot;, price: 5},\n    {name: &quot;\u725b\u5976&quot;, price: 8},\n    {name: &quot;\u9762\u5305&quot;, price: 12}\n];\n\nlet cart = [&quot;\u82f9\u679c&quot;, &quot;\u9762\u5305&quot;, &quot;\u9762\u5305&quot;, &quot;\u82f9\u679c&quot;];\n<\/code><\/pre>\n<p><strong>\u8981\u6c42<\/strong>:<\/p>\n<ol>\n<li>\u904d\u5386\u8d2d\u7269\u8f66\uff0c\u6253\u5370\u6bcf\u4e2a\u5546\u54c1<\/li>\n<li>\u8ba1\u7b97\u603b\u4ef7<\/li>\n<li>\u7edf\u8ba1\u6bcf\u79cd\u5546\u54c1\u7684\u6570\u91cf<\/li>\n<\/ol>\n<h3>\u7ec3\u4e60 3: \u5b9e\u6218\u5e94\u7528<\/h3>\n<p><strong>\u4efb\u52a1<\/strong>: \u521b\u5efa\u4e00\u4e2a\u5b66\u751f\u6210\u7ee9\u7ba1\u7406\u7cfb\u7edf<\/p>\n<p><strong>\u6570\u636e<\/strong>:<\/p>\n<pre><code class=\"language-javascript\">let students = [\n    {name: &quot;\u5c0f\u660e&quot;, scores: [85, 90, 88]},\n    {name: &quot;\u5c0f\u7ea2&quot;, scores: [92, 87, 95]},\n    {name: &quot;\u5c0f\u521a&quot;, scores: [78, 85, 82]}\n];\n<\/code><\/pre>\n<p><strong>\u8981\u6c42<\/strong>:<\/p>\n<ol>\n<li>\u8ba1\u7b97\u6bcf\u4e2a\u5b66\u751f\u7684\u5e73\u5747\u5206<\/li>\n<li>\u627e\u51fa\u603b\u5206\u6700\u9ad8\u7684\u5b66\u751f<\/li>\n<li>\u7edf\u8ba1\u6240\u6709\u5b66\u751f\u7684\u5e73\u5747\u5206<\/li>\n<li>\u8f93\u51fa\u683c\u5f0f\u5316\u7684\u6210\u7ee9\u5355<\/li>\n<\/ol>\n<p><strong>\u8f93\u51fa\u793a\u4f8b<\/strong>:<\/p>\n<pre><code>=== \u6210\u7ee9\u5355 ===\n\u5c0f\u660e: \u5e73\u5747 87.7\n\u5c0f\u7ea2: \u5e73\u5747 91.3\n\u5c0f\u521a: \u5e73\u5747 81.7\n\n\u6700\u9ad8\u5206: \u5c0f\u7ea2 (\u603b\u5206 274)\n\u73ed\u7ea7\u5e73\u5747\u5206: 86.9\n<\/code><\/pre>\n<h2>\ud83c\udf93 \u4eca\u65e5\u6311\u6218<\/h2>\n<p><strong>\u6311\u6218\u4efb\u52a1<\/strong>: \u8bbe\u8ba1\u4e00\u4e2a\u7b80\u5355\u7684\u6587\u5b57\u6e38\u620f<\/p>\n<p><strong>\u6e38\u620f\u89c4\u5219<\/strong>:<\/p>\n<ol>\n<li>\u7535\u8111\u968f\u673a\u751f\u6210\u4e00\u4e2a 1-100 \u7684\u6570\u5b57<\/li>\n<li>\u73a9\u5bb6\u731c\u6d4b\u6570\u5b57\uff0c\u6700\u591a 10 \u6b21\u673a\u4f1a<\/li>\n<li>\u6bcf\u6b21\u63d0\u793a&quot;\u592a\u5927&quot;\u6216&quot;\u592a\u5c0f&quot;<\/li>\n<li>\u8bb0\u5f55\u6bcf\u6b21\u731c\u6d4b\u7684\u5386\u53f2<\/li>\n<\/ol>\n<p><strong>\u8981\u6c42<\/strong>:<\/p>\n<ul>\n<li>\u4f7f\u7528\u6570\u7ec4\u5b58\u50a8\u731c\u6d4b\u5386\u53f2<\/li>\n<li>\u7528\u5faa\u73af\u63a7\u5236\u6e38\u620f\u6b21\u6570<\/li>\n<li>\u663e\u793a\u731c\u6d4b\u5386\u53f2\u548c\u5efa\u8bae<\/li>\n<li>\u731c\u4e2d\u6216\u7528\u5b8c\u6b21\u6570\u540e\u663e\u793a\u7ed3\u679c<\/li>\n<\/ul>\n<p><strong>\u793a\u4f8b\u8f93\u51fa<\/strong>:<\/p>\n<pre><code>=== \u731c\u6570\u5b57\u6e38\u620f ===\n\u6211\u5df2\u7ecf\u60f3\u597d\u4e86\u4e00\u4e2a 1-100 \u7684\u6570\u5b57\uff0c\u4f60\u6709 10 \u6b21\u673a\u4f1a\uff01\n\n\u7b2c 1 \u6b21\u731c\u6d4b (50): \u592a\u5927\u4e86\uff01\n\u7b2c 2 \u6b21\u731c\u6d4b (25): \u592a\u5c0f\u4e86\uff01\n\u7b2c 3 \u6b21\u731c\u6d4b (37): \u592a\u5c0f\u4e86\uff01\n...\n\n\u731c\u6d4b\u5386\u53f2: [50, 25, 37, ...]\n\u606d\u559c\u4f60\uff01\u7b54\u6848\u5c31\u662f 42\uff01\n<\/code><\/pre>\n<h2>\ud83d\udca1 \u5e38\u7528\u6570\u7ec4\u65b9\u6cd5<\/h2>\n<pre><code class=\"language-javascript\">let nums = [1, 2, 3, 4, 5];\n\n\/\/ \u6dfb\u52a0\u5143\u7d20\nnums.push(6);        \/\/ \u672b\u5c3e\u6dfb\u52a0 -&gt; [1,2,3,4,5,6]\nnums.unshift(0);     \/\/ \u5f00\u5934\u6dfb\u52a0 -&gt; [0,1,2,3,4,5,6]\n\n\/\/ \u5220\u9664\u5143\u7d20\nnums.pop();          \/\/ \u5220\u9664\u672b\u5c3e -&gt; [0,1,2,3,4,5]\nnums.shift();        \/\/ \u5220\u9664\u5f00\u5934 -&gt; [1,2,3,4,5]\n\n\/\/ \u67e5\u627e\nnums.indexOf(3);     \/\/ \u8fd4\u56de 3 \u7684\u7d22\u5f15 (2)\nnums.includes(4);    \/\/ true - \u662f\u5426\u5305\u542b 4\n\n\/\/ \u6570\u7ec4\u53d8\u5b57\u7b26\u4e32\nnums.join(&quot;, &quot;);     \/\/ &quot;1, 2, 3, 4, 5&quot;\nnums.toString();     \/\/ &quot;1,2,3,4,5&quot;\n<\/code><\/pre>\n<h2>\u26a0\ufe0f \u5e38\u89c1\u9519\u8bef<\/h2>\n<h3>\u9519\u8bef 1: \u6570\u7ec4\u7d22\u5f15\u8d8a\u754c<\/h3>\n<pre><code class=\"language-javascript\">let arr = [1, 2, 3];\nconsole.log(arr[5]);  \/\/ undefined - \u6ca1\u6709\u7d22\u5f15 5\n<\/code><\/pre>\n<h3>\u9519\u8bef 2: \u5faa\u73af\u6761\u4ef6\u9519\u8bef<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u9519\u8bef: \u5fd8\u8bb0\u66f4\u65b0\u53d8\u91cf\uff0c\u53d8\u6210\u6b7b\u5faa\u73af\nlet i = 0;\nwhile (i &lt; 5) {\n    console.log(i);\n    \/\/ \u5fd8\u8bb0 i++ - \u4f1a\u4e00\u76f4\u6253\u5370 0\n}\n\n\/\/ \u6b63\u786e\nwhile (i &lt; 5) {\n    console.log(i);\n    i++;  \/\/ \u8bb0\u5f97\u66f4\u65b0\n}\n<\/code><\/pre>\n<h3>\u9519\u8bef 3: \u6df7\u6dc6\u8d4b\u503c\u548c\u6bd4\u8f83<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u9519\u8bef: \u5e94\u8be5\u7528 === \u800c\u4e0d\u662f =\nfor (let i = 0; i = 5; i++) {  \/\/ \u6b7b\u5faa\u73af!\n    \/\/ ...\n}\n\n\/\/ \u6b63\u786e\nfor (let i = 0; i &lt; 5; i++) {\n    \/\/ ...\n}\n<\/code><\/pre>\n<h2>\ud83c\udfaf \u8c03\u8bd5\u6280\u5de7<\/h2>\n<h3>1. \u6253\u5370\u6570\u7ec4<\/h3>\n<pre><code class=\"language-javascript\">let arr = [1, 2, 3];\nconsole.log(arr);         \/\/ [1, 2, 3]\nconsole.log(arr[0]);      \/\/ 1\nconsole.log(arr.length);  \/\/ 3\n<\/code><\/pre>\n<h3>2. \u5faa\u73af\u4e2d\u7684\u8c03\u8bd5<\/h3>\n<pre><code class=\"language-javascript\">for (let i = 0; i &lt; 5; i++) {\n    console.log(`\u7b2c ${i} \u6b21\u5faa\u73af`);  \/\/ \u8ddf\u8e2a\u5faa\u73af\u6b21\u6570\n    \/\/ \u4f60\u7684\u4ee3\u7801\n}\n<\/code><\/pre>\n<h3>3. \u4f7f\u7528 debugger<\/h3>\n<pre><code class=\"language-javascript\">let numbers = [1, 2, 3, 4, 5];\ndebugger;  \/\/ \u7a0b\u5e8f\u4f1a\u5728\u8fd9\u91cc\u6682\u505c\nfor (let num of numbers) {\n    console.log(num);\n}\n<\/code><\/pre>\n<h2>\ud83d\udcda \u5ef6\u4f38\u9605\u8bfb<\/h2>\n<ul>\n<li><strong>\u4e0b\u4e00\u8282<\/strong>: Day 8 &#8211; \u5bf9\u8c61<\/li>\n<li><strong>\u76f8\u5173<\/strong>: Day 6 &#8211; \u6570\u7ec4\u4e0e\u5bf9\u8c61\uff08\u672c\u8282\u6df1\u5165\u8bb2\u89e3\uff09<\/li>\n<li><strong>\u8fdb\u9636<\/strong>: forEach\u3001map\u3001filter \u7b49\u9ad8\u9636\u6570\u7ec4\u65b9\u6cd5<\/li>\n<\/ul>\n<hr>\n<p><strong>\u5b66\u4e60\u65f6\u95f4<\/strong>: 2026-03-08<br \/>\n<strong>\u96be\u5ea6<\/strong>: \u2b50\u2b50\u2b50\u2606\u2606<br \/>\n<strong>\u9884\u8ba1\u7528\u65f6<\/strong>: 2-3 \u5c0f\u65f6<br \/>\n<strong>\u5173\u952e\u8bcd<\/strong>: \u6570\u7ec4, \u5faa\u73af, for, while<br \/>\n<strong>\u76f8\u5173\u6807\u7b7e<\/strong>: #02-\u53d8\u91cf\u4e0e\u6570\u636e<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Day 7: \u6570\u7ec4\u548c\u5faa\u73af \ud83c\udfaf \u5b66\u4e60\u76ee\u6807 \u7406\u89e3\u6570\u7ec4\u7684\u6982\u5ff5\u548c\u7528\u9014 \u638c\u63e1 for \u5faa\u73af\u548c while \u5faa\u73af\u7684\u4f7f\u7528 \u5b66 &#8230; <a title=\"Day-7-\u6570\u7ec4\u548c\u5faa\u73af\" class=\"read-more\" href=\"https:\/\/www.resilence.cn\/?p=233\" aria-label=\"\u7ee7\u7eed\u9605\u8bfbDay-7-\u6570\u7ec4\u548c\u5faa\u73af\">\u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-233","post","type-post","status-publish","format-standard","hentry","category-studycoding"],"_links":{"self":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/233","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=233"}],"version-history":[{"count":1,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/233\/revisions"}],"predecessor-version":[{"id":234,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/233\/revisions\/234"}],"wp:attachment":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=233"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=233"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=233"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}