How to work with arrays of arrays (nested arrays/two-dimensional array)

Code that creates an array of arrays

      
      $times_table = array(); // create an empty array

      for ($i = 0; $i <= 12; $i++) {

        for ($j = 0; $j <= 12; $j++) {

          $times_table[$i][$j] = $i * $j;

        }

      }

Code that adds values to the array of arrays

      
      for ($i = 0; $i <= 12; $i++) {

        for ($j = 0; $j <= 12; $j++) {

          $times_table[$i][$j] = $i * $j;

        }

      }

Code that refers to elements in the array of arrays

      echo $times_table[4][3];

      echo $times_table[7][6];
      \$times_table[4][3] = " . $times_table[4][3] . "
\n");
      echo("\$times_table[7][6] = " . $times_table[7][6] . "
\n");
      ?>
    

Code that creates a cart array

      $cart = array();

      $item['itemCode'] = 123;

      $item['itemName'] = 'Visual Basic';

      $item['itemCost'] = 57.5;

      $item['itemQuantity'] = 5;

      $cart[] = $item;

      $item['itemCode'] = 456;

      $item['itemName'] = 'Java';

      $item['itemCost'] = 59.5;

      $item['itemQuantity'] = 2;

      $cart[] = $item; // add item array to cart array
      \$cart = ");
      print_r($cart);
      echo("
\n");
      ?>
    

Code that creates and adds another associative array to the cart array

      
      $item = array(); // create an empty item array

Code that refers to the elements in the array of associative arrays

      echo $cart[0]['itemCode']; // displays 123

      echo $cart[1]['itemName']; // displays Java 
      \$cart[0]['itemcode'] = " . $cart[0]['itemCode']); // displays 123
      echo("
\n\$cart[1]['itemcode'] = " . $cart[1]['itemName'] . "
\n"); // displays Java 
      ?>
    

A more concise way to create an array of arrays

      
      $cart = array(

        array('itemCode' => 123, 'itemName' => 'Visual Basic', 'itemCost' => 57.5, 'itemQuantity' => 5), 

          array('itemCode' => 456, 'itemName' => 'Java', 'itemCost' => 59.5, 'itemQuantity' => 2)

      );

To refer to the elements in an array of arrays, you use two index values for each element. The first index is for an element in the outer array. The second index is for an element in the inner array.

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