{"id":2991,"date":"2025-03-19T21:43:07","date_gmt":"2025-03-19T13:43:07","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2991"},"modified":"2025-03-19T21:43:07","modified_gmt":"2025-03-19T13:43:07","slug":"php-while-%e5%be%aa%e7%8e%af%e8%af%a6%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/19\/php-while-%e5%be%aa%e7%8e%af%e8%af%a6%e8%a7%a3\/","title":{"rendered":"PHP while \u5faa\u73af\u8be6\u89e3"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">1. \u4ec0\u4e48\u662f <code>while<\/code> \u5faa\u73af\uff1f<\/h2>\n\n\n\n<p><code>while<\/code> \u5faa\u73af\u7528\u4e8e\u5728\u6307\u5b9a\u6761\u4ef6\u4e3a <code>true<\/code> \u65f6 <strong>\u91cd\u590d\u6267\u884c\u4ee3\u7801\u5757<\/strong>\u3002\u5f53\u6761\u4ef6\u53d8\u4e3a <code>false<\/code> \u65f6\uff0c\u5faa\u73af\u505c\u6b62\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udccc \u8bed\u6cd5\uff1a<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>while (\u6761\u4ef6) {\n    \/\/ \u4ee3\u7801\u5757\n}<\/code><\/pre>\n\n\n\n<p>\u2705 <strong>\u7279\u70b9<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9002\u7528\u4e8e <strong>\u5faa\u73af\u6b21\u6570\u4e0d\u786e\u5b9a<\/strong> \u7684\u60c5\u51b5<\/li>\n\n\n\n<li><strong>\u5148\u5224\u65ad\u6761\u4ef6\uff0c\u518d\u6267\u884c\u5faa\u73af\u4f53<\/strong><\/li>\n\n\n\n<li>\u53ea\u8981\u6761\u4ef6 <strong>\u59cb\u7ec8\u4e3a true<\/strong>\uff0c\u5faa\u73af\u5c31\u4f1a <strong>\u65e0\u9650\u6267\u884c<\/strong>\uff08\u26a0\ufe0f\u6ce8\u610f\u907f\u514d\u6b7b\u5faa\u73af\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2. <code>while<\/code> \u5faa\u73af\u793a\u4f8b<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>\u793a\u4f8b 1\uff1a\u6253\u5370 1-5<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$i = 1;\nwhile ($i &lt;= 5) {\n    echo \"\u5f53\u524d\u6570\u503c\uff1a\" . $i . \"&lt;br&gt;\";\n    $i++;\n}\n?&gt;<\/code><\/pre>\n\n\n\n<p>\ud83d\udd39 <strong>\u89e3\u6790<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u521d\u59cb <code>$i = 1<\/code><\/li>\n\n\n\n<li><code>while ($i &lt;= 5)<\/code>\uff1a\u53ea\u8981 <code>$i<\/code> \u5c0f\u4e8e\u7b49\u4e8e 5\uff0c\u6267\u884c\u5faa\u73af\u4f53<\/li>\n\n\n\n<li><code>$i++<\/code> \u8ba9 <code>$i<\/code> \u9010\u6b65\u589e\u52a0\uff0c\u907f\u514d\u6b7b\u5faa\u73af<\/li>\n<\/ul>\n\n\n\n<p>\ud83d\udd39 <strong>\u8f93\u51fa\u7ed3\u679c<\/strong>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\u5f53\u524d\u6570\u503c\uff1a1\n\u5f53\u524d\u6570\u503c\uff1a2\n\u5f53\u524d\u6570\u503c\uff1a3\n\u5f53\u524d\u6570\u503c\uff1a4\n\u5f53\u524d\u6570\u503c\uff1a5<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">3. <code>while<\/code> \u5faa\u73af\u7684\u5e38\u89c1\u5e94\u7528<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>\u793a\u4f8b 2\uff1a\u7d2f\u52a0\u6c42\u548c<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$sum = 0;\n$i = 1;\nwhile ($i &lt;= 100) {\n    $sum += $i;\n    $i++;\n}\necho \"1 \u5230 100 \u7684\u603b\u548c\u662f\uff1a\" . $sum;\n?&gt;<\/code><\/pre>\n\n\n\n<p>\ud83d\udd39 <strong>\u89e3\u6790<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d8\u91cf <code>$sum<\/code> \u7528\u4e8e\u7d2f\u52a0<\/li>\n\n\n\n<li><code>$i<\/code> \u4ece <code>1<\/code> \u9012\u589e\u5230 <code>100<\/code><\/li>\n\n\n\n<li><code>while ($i &lt;= 100)<\/code> \u63a7\u5236\u5faa\u73af <strong>\u8fd0\u884c 100 \u6b21<\/strong><\/li>\n<\/ul>\n\n\n\n<p>\ud83d\udd39 <strong>\u8f93\u51fa\u7ed3\u679c<\/strong>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>1 \u5230 100 \u7684\u603b\u548c\u662f\uff1a5050<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>\u793a\u4f8b 3\uff1a\u8bfb\u53d6\u6570\u636e\u5e93\u6570\u636e<\/strong><\/h3>\n\n\n\n<p>\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c<code>while<\/code> \u5f80\u5f80\u7528\u4e8e <strong>\u5904\u7406\u6570\u636e\u5e93\u67e5\u8be2\u7ed3\u679c<\/strong>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$conn = new mysqli(\"localhost\", \"root\", \"password\", \"testdb\");\n$sql = \"SELECT name FROM users\";\n$result = $conn-&gt;query($sql);\n\nwhile ($row = $result-&gt;fetch_assoc()) {\n    echo \"\u7528\u6237\uff1a\" . $row&#91;\"name\"] . \"&lt;br&gt;\";\n}\n$conn-&gt;close();\n?&gt;<\/code><\/pre>\n\n\n\n<p>\ud83d\udd39 <strong>\u89e3\u6790<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8fde\u63a5\u6570\u636e\u5e93\u5e76\u67e5\u8be2 <code>users<\/code> \u8868<\/li>\n\n\n\n<li><code>while ($row = $result->fetch_assoc())<\/code> \u9010\u884c\u83b7\u53d6\u6570\u636e\uff0c\u76f4\u5230 <code>NULL<\/code><\/li>\n\n\n\n<li><strong>\u5e38\u7528\u4e8e\u5904\u7406\u6570\u636e\u5e93\u6570\u636e<\/strong><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. <code>do...while<\/code> \u5faa\u73af\uff08\u81f3\u5c11\u6267\u884c\u4e00\u6b21\uff09<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udccc \u8bed\u6cd5\uff1a<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>do {\n    \/\/ \u4ee3\u7801\u5757\n} while (\u6761\u4ef6);<\/code><\/pre>\n\n\n\n<p>\u2705 <strong>\u533a\u522b<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>do...while<\/code> <strong>\u5148\u6267\u884c\u4e00\u6b21\u4ee3\u7801\u5757<\/strong>\uff0c\u7136\u540e\u5224\u65ad\u6761\u4ef6<\/li>\n\n\n\n<li>\u9002\u7528\u4e8e <strong>\u81f3\u5c11\u6267\u884c\u4e00\u6b21<\/strong> \u7684\u60c5\u51b5<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>\u793a\u4f8b 4\uff1a\u5373\u4f7f\u6761\u4ef6\u4e0d\u6ee1\u8db3\uff0c\u4ecd\u7136\u6267\u884c\u4e00\u6b21<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$i = 10;\ndo {\n    echo \"\u5f53\u524d\u503c\uff1a\" . $i . \"&lt;br&gt;\";\n    $i++;\n} while ($i &lt;= 5);\n?&gt;<\/code><\/pre>\n\n\n\n<p>\ud83d\udd39 <strong>\u8f93\u51fa<\/strong>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\u5f53\u524d\u503c\uff1a10<\/code><\/pre>\n\n\n\n<p>\u5373\u4f7f <code>$i=10<\/code>\uff0c\u4f46 <code>do...while<\/code> <strong>\u5148\u6267\u884c\u4e00\u6b21<\/strong>\uff0c\u518d\u5224\u65ad\u662f\u5426\u7ee7\u7eed\u5faa\u73af\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">5. <code>while<\/code> \u5faa\u73af\u5e38\u89c1\u9519\u8bef &amp; \u89e3\u51b3\u65b9\u6848<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\u274c <strong>\u9519\u8bef 1\uff1a\u6b7b\u5faa\u73af<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$i = 1;\nwhile ($i &gt; 0) {  \/\/ \u6ca1\u6709\u7ec8\u6b62\u6761\u4ef6\n    echo $i . \"&lt;br&gt;\";\n}\n?&gt;<\/code><\/pre>\n\n\n\n<p>\u26a0\ufe0f <strong>\u95ee\u9898<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$i<\/code> <strong>\u59cb\u7ec8\u5927\u4e8e 0<\/strong>\uff0c\u5bfc\u81f4 <strong>\u65e0\u9650\u5faa\u73af<\/strong>\uff0c\u7a0b\u5e8f\u5d29\u6e83\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u2705 <strong>\u4fee\u6b63<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$i = 1;\nwhile ($i &lt;= 5) {\n    echo $i . \"&lt;br&gt;\";\n    $i++; \/\/ \u9012\u589e\uff0c\u786e\u4fdd\u6700\u7ec8\u6761\u4ef6\u4e3a false\n}\n?&gt;<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u274c <strong>\u9519\u8bef 2\uff1a\u53d8\u91cf\u672a\u521d\u59cb\u5316<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\nwhile ($i &lt;= 5) {\n    echo $i . \"&lt;br&gt;\";\n    $i++;\n}\n?&gt;<\/code><\/pre>\n\n\n\n<p>\u26a0\ufe0f <strong>\u95ee\u9898<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$i<\/code> <strong>\u672a\u521d\u59cb\u5316<\/strong>\uff0c\u53ef\u80fd\u5bfc\u81f4 <code>Undefined variable<\/code> \u9519\u8bef\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u2705 <strong>\u4fee\u6b63<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;?php\n$i = 1; \/\/ \u5148\u5b9a\u4e49\u53d8\u91cf\nwhile ($i &lt;= 5) {\n    echo $i . \"&lt;br&gt;\";\n    $i++;\n}\n?&gt;<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">6. <code>while<\/code> vs <code>for<\/code> vs <code>do...while<\/code><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><\/th><th><code>while<\/code><\/th><th><code>do...while<\/code><\/th><th><code>for<\/code><\/th><\/tr><\/thead><tbody><tr><td><strong>\u9002\u7528\u573a\u666f<\/strong><\/td><td><strong>\u5faa\u73af\u6b21\u6570\u4e0d\u786e\u5b9a<\/strong><\/td><td>\u81f3\u5c11\u6267\u884c\u4e00\u6b21<\/td><td><strong>\u5faa\u73af\u6b21\u6570\u56fa\u5b9a<\/strong><\/td><\/tr><tr><td><strong>\u6267\u884c\u987a\u5e8f<\/strong><\/td><td><strong>\u5148\u5224\u65ad\u6761\u4ef6<\/strong>\uff0c\u518d\u6267\u884c<\/td><td><strong>\u5148\u6267\u884c<\/strong>\uff0c\u518d\u5224\u65ad<\/td><td>\u5148\u521d\u59cb\u5316\uff0c\u518d\u6267\u884c<\/td><\/tr><tr><td><strong>\u662f\u5426\u4e00\u5b9a\u6267\u884c<\/strong><\/td><td>\u274c \u5426<\/td><td>\u2705 \u662f<\/td><td>\u274c \u5426<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u2705 <strong>\u9009\u62e9\u6307\u5357<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u5faa\u73af\u6b21\u6570\u786e\u5b9a<\/strong> \u279d <code>for<\/code><\/li>\n\n\n\n<li><strong>\u53ef\u80fd\u4e0d\u6267\u884c<\/strong> \u279d <code>while<\/code><\/li>\n\n\n\n<li><strong>\u81f3\u5c11\u6267\u884c\u4e00\u6b21<\/strong> \u279d <code>do...while<\/code><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">7. \u7ec3\u4e60\u9898<\/h2>\n\n\n\n<p>\ud83d\udcdd <strong>\u8bf7\u5c1d\u8bd5\u5b8c\u6210\u4ee5\u4e0b\u4efb\u52a1<\/strong>\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"> <strong>\u7ec3\u4e60 1\uff1a\u8f93\u51fa 1 \u5230 10 \u7684\u5076\u6570<\/strong><\/h3>\n\n\n\n<p><strong>\u63d0\u793a<\/strong>\uff1a\u4f7f\u7528 <code>while<\/code>\uff0c\u5224\u65ad\u5076\u6570 <code>if ($i % 2 == 0)<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"> <strong>\u7ec3\u4e60 2\uff1a\u8ba1\u7b97 1 \u5230 50 \u7684\u5947\u6570\u548c<\/strong><\/h3>\n\n\n\n<p><strong>\u63d0\u793a<\/strong>\uff1a\u7d2f\u52a0\u5947\u6570 <code>if ($i % 2 != 0)<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"> <strong>\u7ec3\u4e60 3\uff1a\u751f\u6210 5 \u4e2a\u968f\u673a\u6570\u5e76\u8f93\u51fa<\/strong><\/h3>\n\n\n\n<p><strong>\u63d0\u793a<\/strong>\uff1a<code>rand(1, 100)<\/code><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udd17 \u76f8\u5173\u53c2\u8003\u94fe\u63a5<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.php.net\/manual\/en\/control-structures.while.php\">PHP while \u5b98\u65b9\u6587\u6863<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.php.net\/manual\/en\/control-structures.do.while.php\">PHP do\u2026while \u5b98\u65b9\u6587\u6863<\/a><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u2705 \u901a\u8fc7\u672c\u6559\u7a0b\uff0c\u4f60\u5df2\u7ecf\u638c\u63e1\u4e86 PHP <strong><code>while<\/code> \u5faa\u73af<\/strong> \u7684\u7528\u6cd5\u3001\u5b9e\u9645\u5e94\u7528\u548c\u5e38\u89c1\u9519\u8bef\uff01\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>1. \u4ec0\u4e48\u662f while \u5faa\u73af\uff1f while \u5faa\u73af\u7528\u4e8e\u5728\u6307\u5b9a\u6761\u4ef6\u4e3a true \u65f6 \u91cd\u590d\u6267\u884c\u4ee3\u7801\u5757\u3002\u5f53\u6761\u4ef6\u53d8\u4e3a  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2992,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[80],"tags":[],"class_list":["post-2991","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-php"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2991","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2991"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2991\/revisions"}],"predecessor-version":[{"id":2993,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2991\/revisions\/2993"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/2992"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2991"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2991"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2991"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}