(PHP 5, PHP 7, PHP 8)
ArrayAccess::offsetGet — 获取一个偏移位置的值
offset需要获取的偏移位置。
Note:
Starting with PHP 5.3.4, the prototype checks were relaxed and it's possible for implementations of this method to return by reference. This makes indirect modifications to the overloaded array dimensions of ArrayAccess objects possible.
A direct modification is one that replaces completely the value of the array dimension, as in
$obj[6] = 7. An indirect modification, on the other hand, only changes part of the dimension, or attempts to assign the dimension by reference to another variable, as in$obj[6][7] = 7or$var =& $obj[6]. Increments with++and decrements with--are also implemented in a way that requires indirect modification.While direct modification triggers a call to ArrayAccess::offsetSet(), indirect modification triggers a call to ArrayAccess::offsetGet(). In that case, the implementation of ArrayAccess::offsetGet() must be able to return by reference, otherwise an
E_NOTICEmessage is raised.
可返回任何类型。
As of PHP 7, offsetExists($offset) must return a TRUE value in order for offsetGet($offset) to be called, otherwise offsetGet($offset) will just return NULL. This was not the case in PHP 5, so if your code suddenly stops working upon upgrade to PHP 7, make sure offsetExists() returns sensible values.