";
$a0[0] = "hamburger"; // Note the odd behavior here
$a0[1] = "pizza";
$a0[2] = "hotdog";
var_dump ($a0);
echo "
";
// $a0 is a string, assigning a value to a certain position of a string
// causes a replacement to the character
unset($a0); // set $a0 back to null
// Let's assign a value to a certain position of an array
$a0[0] = "hamburger"; // This time array indexing works correctly
$a0[1] = "hotdog";
$a0[2] = "pizza";
var_dump ($a0);
echo "
";
echo "Several ways to create arrays
";
// Creating an array
$list[0] = 17;
$list[1] = "Today is my birthday";
$list[] = 42;
var_dump($list);
echo "
";
// An array can also be created using an array constructor
$list = array(17, 24, "45", 91);
var_dump($list);
echo "
";
$list[8] = "skip index";
var_dump($list);
echo "
";
// Another way to create an array
$ages = array("Joe" => 42, "Mary" => 41, "John" => 71);
var_dump($ages);
echo "
";
$ages['Tim'] = 29;
var_dump($ages);
echo "
";
echo "Access array_keys and array_values
";
$name = array_keys($ages);
$age = array_values($ages);
if (sizeof($name) > 0)
if (array_key_exists("Mary", $ages))
echo "A key \"Mary\" exists in an array \$ages
";
else
echo "A key \"Mary\" does not exist in an array \$ages
";
// Functions we can use to access an element in an array
// current() - returns the value of the current element in an array
// end() - moves the internal pointer to, and outputs, the last element in the array
// next() - moves the internal pointer to, and outputs, the next element in the array
// prev() - moves the internal pointer to, and outputs, the previous element in the array
// each() - returns the current element key and value, and moves the internal pointer forward
// reset() -- reset the internal pointer to the first element in the array
// let's iterate the array
$curr = current($ages);
while ($curr):
echo $curr ."
";
$curr = next($ages); // point to the next item in an array
// notice that the value is displayed
endwhile;
// let's iterate the array_keys
$curr = current($name);
while ($curr):
echo $curr ."
";
$curr = next($name); // point to the next item in an array_key
// array $name builds index of each key
endwhile;
// Once we have iterated on the array, to do so again we need to reset
// it first, as shown below.
reset($ages);
while ($curr = each($ages)):
$k = $curr["key"];
$v = $curr["value"];
echo "key is $k and value is $v
";
endwhile;
// Use the ksort() function to sort by keys
ksort($ages);
// echo $ages; // what happen if we echo an array ?
// There are several ways to display information.
// var_dump() function prints everything about a variable (type, size, value)
// print_r() function prints human-readable information about a variable.
print_r($ages);
echo "
";
// Use sort() function to sort by values
sort($ages);
print_r($ages);
echo "
";
?>
sort and ksort example
31, "Al" => 27, "Gandalf" => "wizard", "Betty" => 42, "Frodo" => "hobbit");
echo "Original array
";
// print original array
foreach ($original as $key => $value)
print("[$key] => $value
");
$new = $original;
sort($new);
echo "
Sorted array (using sort() function)
";
foreach ($new as $key => $value) // syntax: foreach (array as key => value) then loop body
print("[$key] => $value
");
$new = $original;
ksort($new);
echo "
Sorted array (using ksort() function)
";
foreach ($new as $key => $value)
print("[$key] => $value
");
?>