title: Are PHP Namespaces dependent on path of file?
body: <p>In YII2 Framework
  Path of File is root\vendor\yiisoft\yii2-httpclient\Client.php</p>
  <p>Namespace defined in above mentioned file is - namespace yii\httpclient;</p>
  <p>Now when I use this namespace in other file while setting up Google ReCaptcha</p>
  <p>by writing &quot;use yii\httpclient\Client&quot;</p>
  <p>then I am getting error &quot;Class yii\httpclient\Client&quot; not found</p>
  <p>So I want to know whether namespaces are path dependent ? or is there a routing file or htaccess..etc where I can define the actual path of namespaces used in project, which YII2 compiler will refer to locate the file / class ?</p>