The global Keyword Normally, when you create a variable inside a function, that variable is local, and can only be used inside that function. To create a global variable inside a function, you can use the global keyword.
$GLOBALS is a PHP super global variable which is used to access global variables from anywhere in the PHP script (also from within functions or methods). PHP stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable.
The global keyword imports variables from the global scope into the local scope of a function.
A variable starts with the $ sign, followed by the name of the variable. A variable name must start with a letter or the underscore character. A variable name cannot start with a number. A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
The $GLOBALS
array can be used instead:
$GLOBALS['a'] = 'localhost';
function body(){
echo $GLOBALS['a'];
}
From the Manual:
An associative array containing references to all variables which are currently defined in the global scope of the script. The variable names are the keys of the array.
If you have a set of functions that need some common variables, a class with properties may be a good choice instead of a global:
class MyTest
{
protected $a;
public function __construct($a)
{
$this->a = $a;
}
public function head()
{
echo $this->a;
}
public function footer()
{
echo $this->a;
}
}
$a = 'localhost';
$obj = new MyTest($a);
If the variable is not going to change you could use define
Example:
define('FOOTER_CONTENT', 'Hello I\'m an awesome footer!');
function footer()
{
echo FOOTER_CONTENT;
}
If a variable is declared outside of a function its already in global scope. So there is no need to declare. But from where you calling this variable must have access to this variable. If you are calling from inside a function you have to use global
keyword:
$variable = 5;
function name()
{
global $variable;
$value = $variable + 5;
return $value;
}
Using global keyword outside a function is not an error. If you want to include this file inside a function you can declare the variable as global
.
// config.php
global $variable;
$variable = 5;
// other.php
function name()
{
require_once __DIR__ . '/config.php';
}
You can use $GLOBALS
as well. It's a superglobal so it has access everywhere.
$GLOBALS['variable'] = 5;
function name()
{
echo $GLOBALS['variable'];
}
Depending on your choice you can choose either.
Add your variables in $GLOBALS super global array like
$GLOBALS['variable'] = 'localhost';
and use it globally
or you can use constant which are accessible throughout the script
define('HOSTNAME', 'localhost');
This answer is very late but what I do is set a class that holds Booleans, arrays, and integer-initial values as global scope static variables. Any constant strings are defined as such.
define("myconstant", "value");
class globalVars {
static $a = false;
static $b = 0;
static $c = array('first' => 2, 'second' => 5);
}
function test($num) {
if (!globalVars::$a) {
$returnVal = 'The ' . myconstant . ' of ' . $num . ' plus ' . globalVars::$b . ' plus ' . globalVars::$c['second'] . ' is ' . ($num + globalVars::$b + globalVars::$c['second']) . '.';
globalVars::$a = true;
} else {
$returnVal = 'I forgot';
}
return $returnVal;
}
echo test(9); ---> The value of 9 + 0 + 5 is 14.
echo "<br>";
echo globalVars::$a; ----> 1
The static
keywords must be present in the class else the vars $a, $b, and $c will not be globally scoped.
You can try the keyword use
in Closure functions or Lambdas if this fits your intention... PHP 7.0 though. Not that's its better, but just an alternative.
$foo = "New";
$closure = (function($bar) use ($foo) {
echo "$foo $bar";
})("York");
demo | info
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With