$_SERVER
$_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.
The example below shows how to use some of the elements in $_SERVER:
ExampleGet your own PHP Server
echo $_SERVER['PHP_SELF'];
echo $_SERVER['SERVER_NAME'];
echo $_SERVER['HTTP_HOST'];
echo $_SERVER['HTTP_REFERER'];
echo $_SERVER['HTTP_USER_AGENT'];
echo...
$GLOBALS is an array that contains all global variables.
Global Variables
Global variables are variables that can be accessed from any scope.
Variables of the outer most scope are automatically global variables, and can be used by any scope, e.g. inside a function.
To use a global variable inside a function you have to either define them as global with the global keyword,...
Superglobals were introduced in PHP 4.1.0, and are built-in variables that are always available in all scopes.
PHP Global Variables - Superglobals
Some predefined variables in PHP are "superglobals", which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special.
The PHP superglobal variables...
PHP Array Functions
PHP has a set of built-in functions that you can use on arrays.
Function
Description
array()
Creates an array
array_change_key_case()
Changes all keys in an array to lowercase or uppercase
array_chunk()
Splits an array into chunks of arrays
array_column()
Returns the values from a single column in the input array
array_combine()
Creates...
In the previous pages, we have described arrays that are a single list of key/value pairs.
However, sometimes you want to store values with more than one key. For this, we have 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....
The elements in an array can be sorted in alphabetical or numerical order, descending or ascending.
PHP - Sort Functions For Arrays
In this chapter, we will go through the following PHP array sort functions:
sort() - sort arrays in ascending order
rsort() - sort arrays in descending order
asort() - sort associative arrays in ascending order, according to the value...
Remove Array Item
To remove an existing item from an array, you can use the array_splice() function.
With the array_splice() function you specify the index (where to start) and how many items you want to delete.
ExampleGet your own PHP Server
Remove the second item:
$cars = array("Volvo", "BMW", "Toyota");
array_splice($cars, 1, 1);
Try it Yourself »
After...
Add Array Item
To add items to an existing array, you can use the bracket [] syntax.
ExampleGet your own PHP Server
Add one more item to the fruits array:
$fruits = array("Apple", "Banana", "Cherry");
$fruits[] = "Orange";
Try it Yourself »
Associative Arrays
To add items to an associative array, or key/value array, use brackets [] for the key,...
Update Array Item
To update an existing array item, you can refer to the index number for indexed arrays, and the key name for associative arrays.
ExampleGet your own PHP Server
Change the second array item from "BMW" to "Ford":
$cars = array("Volvo", "BMW", "Toyota");
$cars[1] = "Ford";
Try it Yourself »
Note: The first item has index 0.
To update items from...
Access Array Item
To access an array item, you can refer to the index number for indexed arrays, and the key name for associative arrays.
ExampleGet your own PHP Server
Access an item by referring to its index number:
$cars = array("Volvo", "BMW", "Toyota");
echo $cars[2];
Try it Yourself »
Note: The first item has index 0.
To access items from an associative...
Create Array
You can create arrays by using the array() function:
ExampleGet your own PHP Server
$cars = array("Volvo", "BMW", "Toyota");
Try it Yourself »
You can also use a shorter syntax by using the [] brackets:
Example
$cars = ["Volvo", "BMW", "Toyota"];
Try it Yourself »
Multiple Lines
Line breaks are not important, so an array...
PHP Associative Arrays
Associative arrays are arrays that use named keys that you assign to them.
ExampleGet your own PHP Server
$car = array("brand"=>"Ford", "model"=>"Mustang", "year"=>1964);
var_dump($car);
Try it Yourself »
Access Associative Arrays
To access an array item you can refer to the key name.
Example
Display the model of the car:
$car =...
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