PHP Multidimensional Arrays

PHP - Multidimensional Arrays

A multidimensional array is an array containing one or more arrays.

PHP supports multidimensional arrays that are two, three, four, five, or more levels deep. However, arrays more than three levels deep are hard to manage for most people.

PHP - Two-dimensional Arrays

A two-dimensional array is an array of arrays (a three-dimensional array is an array of arrays of arrays).

Take a look at the following table:

We can store the data from the table above in a two-dimensional array, like this:

$cars = array (
  array("Volvo", 22, 18),
  array("BMW", 15, 13),
  array("Saab", 5, 2),
  array("Land Rover", 17, 15)
);

Now the two-dimensional $cars array contains four arrays, and it has two indices: row and column.

To access to the elements of the $cars array we must point to the two indices (row and column):

Example

echo $cars[0][0].": In stock: ".$cars[0][1].", sold: ".$cars[0][2].".<br>";
echo $cars[1][0].": In stock: ".$cars[1][1].", sold: ".$cars[1][2].".<br>";
echo $cars[2][0].": In stock: ".$cars[2][1].", sold: ".$cars[2][2].".<br>";
echo $cars[3][0].": In stock: ".$cars[3][1].", sold: ".$cars[3][2].".<br>";

The dimension of an array indicates the number of indices you need to select an element. - For a two-dimensional array you need two indices to select an element - For a three-dimensional array you need three indices to select an element

PHP - Looping Through Multidimensional Arrays

To loop through a multidimensional array, use a for loop or a foreach loop.

Here, we use a for loop inside another for loop to get the elements of the $cars array (we still have to point to the two indices):

Example

for ($row = 0; $row < 4; $row++) {
  echo "<p><b>Row number $row</b></p>";
  echo "<ul>";
    for ($col = 0; $col < 3; $col++) {
      echo "<li>".$cars[$row][$col]."</li>";
    }
  echo "</ul>";
}

Here, we use a foreach loop inside another foreach loop to get the elements of the $cars array.

Here we put the result in an HTML table:

Example

echo "<table>";
echo "<tr><th>Brand</th><th>Stock</th><th>Sold</th></tr>";

foreach ($cars as $row) {
  echo "<tr>";
  foreach ($row as $cell) {
    echo "<td>" . $cell . "</td>";
  }
  echo "</tr>";
}
echo "</table>";

Complete PHP Array Reference

For a complete reference of all array functions, go to the complete PHP Array Reference.

The reference contains a brief description, and examples of use, for each function!