PHP - Manual: Arrays and Array-style COM properties
Many COM objects expose their properties as arrays, or using array-style access.
Access multi-dimensional arrays, or COM properties that require multiple parameters using PHP array syntax. You can also write or set properties using this technique.
Iterate SafeArrays ("true" arrays) using the foreach control structure. This works because SafeArrays include information about their size. If an array-style property implements IEnumVariant then you can also use foreach for that property too; take a look at For Each for more information on this topic.