php object-oriented problem

<code>class testClass{

public $str_md5 = md5('fefsffa');
public static function testFunction(){

//.....
}

}
</code>

My question is: Why does the md5() function report an error when used as shown above? ? Can't the attributes in PHP object-oriented use PHP's own methods? ? ?

Reply content:

<code>class testClass{

public $str_md5 = md5('fefsffa');
public static function testFunction(){

//.....
}

}
</code>

My question is: Why does the md5() function report an error when used as shown above? ? Can't the attributes in PHP object-oriented use PHP's own methods? ? ?

Because the documentation clearly stipulates that attributes cannot be declared in this way.

http://php.net/manual/en/lang...

You cannot use functions for initialization (only constants). You can initialize $this->str_md5 in __constrct

Class attributes cannot be directly assigned using functions.
For example in a class,
class One{

<code>public $str = 'abc'; //这样没问题
public $str = md5('abc'); //使用函数赋值则会报错</code>

}
You need to define attributes before assigning values.

Static methods cannot call non-static properties