Welcome to our exploration of Nested Data Structures in PHP. After understanding the basics of PHP arrays, we'll delve into nested associative arrays and multidimensional arrays. These structures enable us to handle complex and hierarchical data, which is typical in real-world scenarios. This lesson will guide you through a recap of the basics, the creation and modification of nested arrays, as well as common operations.

As a quick recap, PHP associative arrays store key-value pairs, and indexed arrays store elements in a linear fashion with numeric indices. These structures can be nested. Here's a simple example of a school directory using associative arrays:

Just like their non-nested versions, creating nested structures in PHP is straightforward.

Nested Associative Array:

Nested Indexed Array: