Arrays in PHP

Arrays in PHP allows us to store more values into one variable which makes access to the values much easier.

The most basic way to store values in PHP is to use variables with different names.

$car1 = "Saab";
$car2 = "Volvo";
$car3 = "BMW";

You can find out more about variables in

  Start learning PHP - part 1

In PHP and also in other programming languages there is also a more efficient way to store values in arrays.

To define an array we set name of a variable and add an index.
    
Example with variable $cars:

$cars[0] = "Saab";
$cars[1] = "Volvo";
$cars[2] = "BMW";
$cars[3] = "Toyota";

echo $cars[0] . ", " . $cars[1];

In the example above we defined an array and used echo to print out the values.

Short way for defining array is to use keyword array.

Instead of indexes we can also use names which can be seen in the example below.

$age = array("Peter" => 32, "John" => "57", "Sarah" => 23);

echo "Sarah is " . $age["Sarah"] . " years old.";

Here we have another way to define the array which is a little longer, but the end result is exactly the same as in the previous step.

$age["Peter"] = 32;
$age["John"] = 57;
$age["Sarah"] = 23;

echo "John is " . $age["John"] . " years old.";

We can also define multidimensional array which you can see in the example below.

$person["Peter"]["age"] = 32;
$person["Peter"]["nickname"] = "Pete";
$person["Peter"]["hair"] = "Brown";

$person["John"]["age"] = 57;
$person["John"]["nickname"] = "Johnny";
$person["John"]["hair"] = "Black";

echo "John is " . $person["John"]["age"] . " years old.";

When we are working with arrays we can also use print_r function which will output all the indexes and values of the array.    

$age["Peter"] = 32;
$age["John"] = 57;
$age["Sarah"] = 23;

print_r($age);

One of the main advantages of using arrays is that you can easily access all the values by using foreach loop.

$age["Peter"] = 32;
$age["John"] = 57;
$age["Sarah"] = 23;

foreach($age as $key=>$value) {
  echo "Value of $key is $value. <br />";   
}

By using foreach we go through all the keys in the array and print out the values.


If you want to know more about using loops in PHP please see

  Start learning PHP - part 2