{"id":2976,"date":"2025-03-18T23:58:22","date_gmt":"2025-03-18T15:58:22","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2976"},"modified":"2025-03-18T23:58:22","modified_gmt":"2025-03-18T15:58:22","slug":"php-switch-%e8%af%ad%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/18\/php-switch-%e8%af%ad%e5%8f%a5\/","title":{"rendered":"PHP Switch \u8bed\u53e5"},"content":{"rendered":"\n

switch<\/code> \u8bed\u53e5\u662f PHP \u4e2d\u7684\u4e00\u79cd\u63a7\u5236\u7ed3\u6784\uff0c\u7528\u4e8e\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u503c\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002\u5b83\u662f\u591a\u4e2a if...else<\/code> \u8bed\u53e5\u7684\u66ff\u4ee3\u65b9\u6848\uff0c\u901a\u5e38\u7528\u4e8e\u5f53\u6709\u591a\u4e2a\u6761\u4ef6\u9700\u8981\u68c0\u67e5\u65f6\uff0c\u4ee5\u4fbf\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u6267\u884c\u6548\u7387\u3002<\/p>\n\n\n\n

1. \u57fa\u672c\u8bed\u6cd5<\/strong><\/h2>\n\n\n\n
switch (expression) {\n    case value1:\n        \/\/ \u5982\u679c expression \u7b49\u4e8e value1\uff0c\u6267\u884c\u6b64\u4ee3\u7801\u5757\n        break;\n    case value2:\n        \/\/ \u5982\u679c expression \u7b49\u4e8e value2\uff0c\u6267\u884c\u6b64\u4ee3\u7801\u5757\n        break;\n    default:\n        \/\/ \u5982\u679c expression \u4e0d\u7b49\u4e8e\u4efb\u4f55 case \u7684\u503c\uff0c\u6267\u884c\u6b64\u4ee3\u7801\u5757\n}<\/code><\/pre>\n\n\n\n
\u8bed\u6cd5\u89e3\u6790\uff1a<\/strong><\/h3>\n\n\n\n
    \n
  • expression<\/code>\uff1a\u8fd9\u662f\u9700\u8981\u8fdb\u884c\u6bd4\u8f83\u7684\u8868\u8fbe\u5f0f\uff0c\u53ef\u4ee5\u662f\u4e00\u4e2a\u53d8\u91cf\u3001\u5e38\u91cf\u3001\u6570\u5b57\u6216\u5b57\u7b26\u4e32\u3002<\/li>\n\n\n\n
  • case value<\/code>\uff1a\u6bcf\u4e2a case<\/code> \u540e\u9762\u8ddf\u4e00\u4e2a\u503c\uff0c\u5982\u679c expression<\/code> \u4e0e\u8fd9\u4e2a\u503c\u5339\u914d\uff0c\u5c31\u6267\u884c\u5bf9\u5e94\u7684\u4ee3\u7801\u5757\u3002<\/li>\n\n\n\n
  • break<\/code>\uff1a\u7528\u4e8e\u8df3\u51fa switch<\/code> \u8bed\u53e5\uff0c\u9632\u6b62\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u4e2a case<\/code>\u3002\u5982\u679c\u7701\u7565 break<\/code>\uff0c\u7a0b\u5e8f\u4f1a\u7ee7\u7eed\u6267\u884c\u540e\u9762\u7684 case<\/code> \u4ee3\u7801\u5757\uff0c\u76f4\u5230\u9047\u5230 break<\/code> \u6216 switch<\/code> \u8bed\u53e5\u7ed3\u675f\u3002<\/li>\n\n\n\n
  • default<\/code>\uff1a\u8fd9\u662f\u4e00\u4e2a\u53ef\u9009\u7684\u90e8\u5206\uff0c\u5f53\u6ca1\u6709\u4efb\u4f55 case<\/code> \u5339\u914d\u65f6\uff0c\u6267\u884c default<\/code> \u4ee3\u7801\u5757\u3002default<\/code> \u8bed\u53e5\u901a\u5e38\u653e\u5728\u6700\u540e\u3002<\/li>\n<\/ul>\n\n\n\n
    \u793a\u4f8b\uff1a<\/strong><\/h3>\n\n\n\n
    <?php\n$day = 3;\n\nswitch ($day) {\n    case 1:\n        echo \"Monday\"; \/\/ \u5982\u679c $day \u4e3a 1\uff0c\u8f93\u51fa \"Monday\"\n        break;\n    case 2:\n        echo \"Tuesday\"; \/\/ \u5982\u679c $day \u4e3a 2\uff0c\u8f93\u51fa \"Tuesday\"\n        break;\n    case 3:\n        echo \"Wednesday\"; \/\/ \u5982\u679c $day \u4e3a 3\uff0c\u8f93\u51fa \"Wednesday\"\n        break;\n    case 4:\n        echo \"Thursday\"; \/\/ \u5982\u679c $day \u4e3a 4\uff0c\u8f93\u51fa \"Thursday\"\n        break;\n    case 5:\n        echo \"Friday\"; \/\/ \u5982\u679c $day \u4e3a 5\uff0c\u8f93\u51fa \"Friday\"\n        break;\n    case 6:\n        echo \"Saturday\"; \/\/ \u5982\u679c $day \u4e3a 6\uff0c\u8f93\u51fa \"Saturday\"\n        break;\n    case 7:\n        echo \"Sunday\"; \/\/ \u5982\u679c $day \u4e3a 7\uff0c\u8f93\u51fa \"Sunday\"\n        break;\n    default:\n        echo \"Invalid day\"; \/\/ \u5982\u679c $day \u4e0d\u5728 1 \u5230 7 \u4e4b\u95f4\uff0c\u8f93\u51fa \"Invalid day\"\n}\n?><\/code><\/pre>\n\n\n\n
    \u8f93\u51fa\uff1a<\/strong><\/p>\n\n\n\n
    Wednesday<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    \u6ce8\u610f\u4e8b\u9879\uff1a<\/strong><\/h2>\n\n\n\n
    1. break<\/code> \u7684\u91cd\u8981\u6027<\/strong><\/h3>\n\n\n\n
    break<\/code> \u8bed\u53e5\u7528\u4e8e\u8df3\u51fa switch<\/code> \u8bed\u53e5\u3002\u5982\u679c\u6ca1\u6709 break<\/code>\uff0c\u7a0b\u5e8f\u4f1a\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u4e2a case<\/code> \u8bed\u53e5\uff0c\u76f4\u5230\u9047\u5230 break<\/code> \u6216\u8005 switch<\/code> \u8bed\u53e5\u7684\u7ed3\u675f\u3002\u8fd9\u88ab\u79f0\u4e3a\u201cfall through\u201d\u3002<\/p>\n\n\n\n
    \u793a\u4f8b\uff1a<\/strong><\/h4>\n\n\n\n
    <?php\n$day = 3;\n\nswitch ($day) {\n    case 1:\n        echo \"Monday\";\n    case 2:\n        echo \"Tuesday\";\n    case 3:\n        echo \"Wednesday\"; \/\/ \u5982\u679c $day \u4e3a 3\uff0c\u8f93\u51fa \"WednesdayTuesday\"\n        break;\n    case 4:\n        echo \"Thursday\";\n        break;\n    default:\n        echo \"Invalid day\";\n}\n?><\/code><\/pre>\n\n\n\n
    \u8f93\u51fa\uff1a<\/strong><\/p>\n\n\n\n
    WednesdayTuesday<\/code><\/pre>\n\n\n\n
    \u8bf4\u660e\uff1a<\/strong>
    \u6ca1\u6709 break<\/code>\uff0c\u56e0\u6b64\u7a0b\u5e8f\u4ece case 3<\/code> \u7ee7\u7eed\u6267\u884c\u540e\u9762\u7684 case<\/code> \u8bed\u53e5\uff0c\u76f4\u5230\u9047\u5230 break<\/code> \u6216\u8005 switch<\/code> \u7ed3\u675f\u3002<\/p>\n\n\n\n
    \n\n\n\n
    2. \u4e0d\u4f7f\u7528 break<\/code> \u7684\u7279\u6b8a\u573a\u666f<\/strong><\/h3>\n\n\n\n
    \u6709\u65f6\u5019\u4f60\u53ef\u80fd\u5e0c\u671b\u591a\u4e2a case<\/code> \u6267\u884c\u76f8\u540c\u7684\u4ee3\u7801\u5757\u3002\u4e3a\u4e86\u5b9e\u73b0\u8fd9\u4e00\u70b9\uff0c\u53ef\u4ee5\u7701\u7565 break<\/code>\uff0c\u8ba9\u591a\u4e2a case<\/code> \u6267\u884c\u540c\u4e00\u4e2a\u4ee3\u7801\u5757\u3002<\/p>\n\n\n\n
    \u793a\u4f8b\uff1a<\/strong><\/h4>\n\n\n\n
    <?php\n$day = 3;\n\nswitch ($day) {\n    case 1:\n    case 2:\n    case 3:\n        echo \"This is a weekday\"; \/\/ \u5982\u679c $day \u4e3a 1, 2, \u6216 3\uff0c\u90fd\u4f1a\u8f93\u51fa \"This is a weekday\"\n        break;\n    case 4:\n    case 5:\n        echo \"This is a weekday too\"; \/\/ \u5982\u679c $day \u4e3a 4 \u6216 5\uff0c\u90fd\u4f1a\u8f93\u51fa \"This is a weekday too\"\n        break;\n    default:\n        echo \"Invalid day\";\n}\n?><\/code><\/pre>\n\n\n\n
    \u8f93\u51fa\uff1a<\/strong><\/p>\n\n\n\n
    This is a weekday<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    3. \u4f7f\u7528\u8868\u8fbe\u5f0f\u4f5c\u4e3a case<\/code> \u503c<\/strong><\/h3>\n\n\n\n
    \u5728 PHP \u4e2d\uff0ccase<\/code> \u540e\u7684\u503c\u53ef\u4ee5\u662f\u5e38\u91cf\u3001\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f\u3002\u8fd9\u4f7f\u5f97 switch<\/code> \u8bed\u53e5\u5177\u6709\u66f4\u591a\u7684\u7075\u6d3b\u6027\u3002<\/p>\n\n\n\n
    \u793a\u4f8b\uff1a<\/strong><\/h4>\n\n\n\n
    <?php\n$a = 2;\n\nswitch ($a) {\n    case 1 + 1:\n        echo \"This is 2\"; \/\/ \u5982\u679c $a \u4e3a 2\uff0c\u8f93\u51fa \"This is 2\"\n        break;\n    case 3:\n        echo \"This is 3\";\n        break;\n    default:\n        echo \"Invalid value\";\n}\n?><\/code><\/pre>\n\n\n\n
    \u8f93\u51fa\uff1a<\/strong><\/p>\n\n\n\n
    This is 2<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    4. \u7c7b\u578b\u8f6c\u6362\uff08Type Juggling\uff09<\/strong><\/h3>\n\n\n\n
    PHP \u7684 switch<\/code> \u8bed\u53e5\u4f1a\u81ea\u52a8\u8fdb\u884c\u7c7b\u578b\u8f6c\u6362\u3002\u8fd9\u610f\u5473\u7740\uff0c\u5f53\u4f60\u6bd4\u8f83 case<\/code> \u548c expression<\/code> \u65f6\uff0cPHP \u4f1a\u5c06\u5b83\u4eec\u7684\u7c7b\u578b\u8f6c\u6362\u6210\u76f8\u540c\u7684\u7c7b\u578b\u6765\u8fdb\u884c\u6bd4\u8f83\u3002<\/p>\n\n\n\n
    \u793a\u4f8b\uff1a<\/strong><\/h4>\n\n\n\n
    <?php\n$var = \"10\"; \/\/ \u5b57\u7b26\u4e32\u7c7b\u578b\n\nswitch ($var) {\n    case 10:\n        echo \"Matched with integer 10\"; \/\/ \u8f93\u51fa: Matched with integer 10\n        break;\n    default:\n        echo \"No match\";\n}\n?><\/code><\/pre>\n\n\n\n
    \u8f93\u51fa\uff1a<\/strong><\/p>\n\n\n\n
    Matched with integer 10<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    \u603b\u7ed3\uff1a<\/strong><\/h2>\n\n\n\n
      \n
    • switch<\/code> \u8bed\u53e5\u53ef\u4ee5\u7528\u6765\u66ff\u4ee3\u591a\u4e2a if...else<\/code> \u5224\u65ad\uff0c\u5c24\u5176\u9002\u7528\u4e8e\u6761\u4ef6\u8f83\u591a\u65f6\u3002<\/li>\n\n\n\n
    • case<\/code> \u540e\u9762\u7684\u503c\u53ef\u4ee5\u662f\u5e38\u91cf\u3001\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f\uff0c\u5e76\u4e14 switch<\/code> \u4f1a\u8fdb\u884c\u7c7b\u578b\u8f6c\u6362\u3002<\/li>\n\n\n\n
    • break<\/code> \u8bed\u53e5\u7528\u4e8e\u8df3\u51fa switch<\/code>\uff0c\u9632\u6b62\u201cfall through\u201d\u3002<\/li>\n\n\n\n
    • default<\/code> \u662f\u53ef\u9009\u7684\uff0c\u5f53\u6ca1\u6709\u4efb\u4f55 case<\/code> \u5339\u914d\u65f6\uff0cdefault<\/code> \u4e2d\u7684\u4ee3\u7801\u4f1a\u88ab\u6267\u884c\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
      switch \u8bed\u53e5\u662f PHP \u4e2d\u7684\u4e00\u79cd\u63a7\u5236\u7ed3\u6784\uff0c\u7528\u4e8e\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u503c\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002\u5b83\u662f\u591a\u4e2a if…el […]<\/p>\n","protected":false},"author":1,"featured_media":2977,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[80],"tags":[],"class_list":["post-2976","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\/2976","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=2976"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2976\/revisions"}],"predecessor-version":[{"id":2978,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2976\/revisions\/2978"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/2977"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2976"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2976"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2976"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}