Core PHP Programming, Third Edition

5.4. Multidimensional Arrays

An array element can be any type of data. You've seen numbers and strings, but you can even put an array inside an array. An array of arrays is also called a multidimensional array. Imagine a 10-by-10 grid. You've got 100 different squares, each of which can have its own value. One way to represent this in code is with a two-dimensional array: a 10-element array of 10-number arrays, 10 rows of 10 columns.

To reference a single element, you first use square brackets to pick the first dimension (row), then use a second pair of brackets to pick the second dimension (column). Row 3, column 7, would be written as $someArray[3][7].

Listing 5.6 initializes a multidimensional array using the array function. This shows that ...