How does PHP combine a String constant and a string in a class to define a variable?

There is a constant DATA_PATH, and a string & quot; file_name & quot; how to define a variable in the class (the constant seems to need 5.7), which indicates DATA_PATH and & quot; file_name & quot;. I can define it outside the class as follows: {code ...} but it won't work in the class: {code ...}... there is a constant DATA_PATH and a string "file_name"

How to define a variable in the class (the constant seems to need 5.7), indicating the combination of DATA_PATH and "file_name.

I can define a class as follows:

$FILE_PATH = DATA_PATH."file_name";

But not in the class:

Class Util {public static $ FILE_PATH = DATA_PATH. "file_name"; // syntax error}

Other methods except upgrading PHP

Reply content:

There is a constant DATA_PATH and a string "file_name"

How to define a variable in the class (the constant seems to need 5.7), indicating the combination of DATA_PATH and "file_name.

I can define a class as follows:

$FILE_PATH = DATA_PATH."file_name";

But not in the class:

Class Util {public static $ FILE_PATH = DATA_PATH. "file_name"; // syntax error}

Other methods except upgrading PHP

The original intention of the subject is not to instantiate it.Util::$FILE_PATHCall this static property?

Yes. Apart from upgrading to PHP v5.6.0, you can directly write the code as follows:

define('DATA_PATH', __DIR__ . DIRECTORY_SEPARATOR);class Util {    public static function getFilePath() {        return DATA_PATH . 'filename';    }}echo Util::getFilePath();

Http://3v4l.org/td8D4 | http://3v4l.org/ML4Ce

Remove static ..
Static member attributes must be directly assigned values.

Defined ('data _ file') or define ('data _ file', DATA_PATH. "file_name ");
Class Util {
Public static $ FILE_PATH = DATA_FILE;
}

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