PHP Multi-Dimensional Arrays: Complete Guide

In PHP, multi-dimensional arrays can be defined by nesting arrays within arrays. For example:

$multiArray = array(
    array(1, 2, 3),
    array('a', 'b', 'c'),
    array(true, false, true)
);

The example above defines a multidimensional array with 3 subarrays, each containing 3 elements. You can also define arrays with more dimensions by nesting arrays within the array as needed.