PHP and MySQL Web Development - P23: PHP and MySQL Web Development teaches the reader to develop dynamic, secure, commercial Web sites. Using the same accessible, popular teaching style of the first edition, this best-selling book has been updated to reflect the rapidly changing landscape of MySQL and PHP. | Multidimensional Arrays 77 Multidimensional Arrays Arrays do not have to be a simple list of keys and values each location in the array can hold another array. This way we can create a two-dimensional array. You can think of a two dimensional array as a matrix or grid with width and height or rows and columns. If we want to store more than one piece of data about each of Bob s products we could use a two-dimensional array. Figure shows Bob s products represented as a two-dimensional array with each row representing an individual product and each column representing a stored product attribute. Code Description Price TIR Tires 100 OIL Oil 10 SPK Spark Plugs 4 product attribute Figure We can store more information about Bob s products in a two- dimensional array. Using PHP we would write the following code to set up the data in the array shown in Figure . products array array TIR array OIL Tires 100 Oil 10 Spark Plugs 4 array SPK You can see from this definition that our products array now contains three arrays. To access the data in a one-dimensional array recall that we need the name of the array and the index of the element. A two-dimensional array is similar except that each element has two indices a row and a column. The top row is row 0 and the far left column is column 0. To display the contents of this array we could manually access each element in order like this echo . products 0 0 . . products 0 1 . . products 0 2 . br echo . products 1 0 . . products 1 1 . . products 1 2 . br echo . products 2 0 . . products 2 1 . . products 2 2 . br 78 Chapter 3 Using Arrays Alternatively we could place a for loop inside another for loop to achieve the same result. for row 0 row 3 row for column 0 column 3 column echo . products row column echo br Both versions of this code produce the same output in the browser TIR Tires 100 OIL Oil 10 SPK Spark Plugs 4 The only difference between the two examples is that your code will be shorter if you use the second version
