instanceof 用于**確定一個 PHP 變量是否屬于某一類**class 的實例： instanceof 也可用來**確定一個變量是不是繼承自某一父類的子類的實例**： 檢查一個對象是否 不是 某個類的實例，可以使用 邏輯運算符 not 。 雖然 instanceof 通常直接與類名一起使用，但也可以使用對象或字符串變量： 如果被檢測的變量不是對象，instanceof 并不發出任何錯誤信息而是返回 false 。 ``` ~~~ think\exception\ErrorException {#141 ▼ #severity: 2 #data: [] #message: "Division by zero" #code: 0 #file: "D:\project\wttree\wttree\app\Test\controller\TestEx.php" #line: 25 trace: {▼ D:\project\wttree\wttree\app\Test\controller\TestEx.php:25 {▼ app\test\controller\TestEx->index() … ? try {\r ? return(1/0);\r ? } catch (\Throwable $e) {\r arguments: {?} } app\test\controller\TestEx->index() {} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Container.php:344 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\route\dispatch\Controller.php:110 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:59 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:66 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\route\dispatch\Controller.php:113 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\route\Dispatch.php:90 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Route.php:772 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:59 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:66 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Route.php:773 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Http.php:216 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Http.php:206 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:59 {?} D:\project\wttree\wttree\vendor\topthink\think-multi-app\src\MultiApp.php:71 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:59 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:66 {?} D:\project\wttree\wttree\vendor\topthink\think-multi-app\src\MultiApp.php:72 {?} think\app\MultiApp->handle() {} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Middleware.php:142 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:85 {?} D:\project\wttree\wttree\vendor\thans\tp-jwt-auth\src\middleware\InjectJwt.php:14 {?} thans\jwt\middleware\InjectJwt->handle() {} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Middleware.php:142 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:85 {?} D:\project\wttree\wttree\vendor\topthink\think-trace\src\TraceDebug.php:71 {?} think\trace\TraceDebug->handle() {} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Middleware.php:142 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:85 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Pipeline.php:66 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Http.php:207 {?} D:\project\wttree\wttree\vendor\topthink\framework\src\think\Http.php:170 {?} D:\project\wttree\wttree\public\index.php:29 {?} } } ~~~ ```