尝试在路径中使用$ value来移动基于此php文件的文件

I am trying to get the file to upload an image or audio file to the following directory

$dir='sites/default/documents/"$patientID"/' but I don't know how to use the exact syntax with the $ sign inside a path.

I used the get method to get the patientID from the controller but still nothing is working

Use this instead : $dir="sites/default/documents/$patientID/";

In your case the variable is considered as a text.

Single quotes do not interpolate values, even if there are double quotes inside them. The initial string must be a double quote string, in order for any interpolation to occur inside of it.

If there's any doubt about the complexity of the variable name, use braces to encapsulate the interpolation. $dir="sites/default/documents/{$patientID}/";