为什么只有一个赋值时数组中的两个元素？

Question

In my PHP(5.4.19) app, I assigned string values to two different arrays. One array is scoped to the method, and the other array is a class property:

class AnyClass{
   public $foo = array();

   public function anyMethod(){
       $bar = array();
       $bar[]       = 'anyTextA';
       $this->foo[] = 'anyTextB';
       return array( $bar, $this->foo );
   }
}

Here is what anyMethod() returns:

Array
    (
        [0] => Array
            (
                [0] => anyTextA
            )

        [1] => Array
            (
                [0] => anyTextB
                [1] => anyTextB
            )

    )

Why are two elements appearing in the second array when only one assignment has taken place?

Answer 1

You must be calling this method more than 1 time.

$this->foo[] = 'anyTextB';

This statement adds one more entry to $this->foo whereas the other statement $bar = array(); creates a new array everytime. So if you run this method two times, you will get two values for $foo but still one value for $bar.

As I asked in the first comment, if you show us how you are creating an instance of that class we will be better able to tell exactly where are you duplicating the call.

Contrary to what is being suggested elsewhere, do not use $this->foo=array();. Debug your issue and resolve what's wrong, rather than just putting up a temporary fix to hide the mistake and build more code upon it.