PHP Variables

Creating (Declaring) PHP Variables

In PHP, a variable starts with the $ sign, followed by the name of the variable:

Example 1:

<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>

Output Variables

The PHP echo statement is often used to output data to the screen.

The following example will show how to output text and a variable:

Example 1:

<?php
$txt = "W3Schools.com";
echo "I love $txt!";
?>

Example 2:

<?php
$txt = "W3Schools.com";
echo "I love " . $txt . "!";
?>

Example 3:

<?php
$txt = "W3Schools.com";
echo "I love " . $txt . "!";
?>

Example 4:

<?php
$x = 5;
$y = 4;
echo $x + $y;
?>

PHP The global Keyword

The global keyword is used to access a global variable from within a function.

To do this, use the global keyword before the variables (inside the function):

Example 1:

<?php
$x = 5;
$y = 10;

function myTest() {
    global $x, $y;
    $y = $x + $y;
}

myTest();
echo $y; // outputs 15?>

Example 2:

<?php
$x = 5;
$y = 10;

function myTest() {
    $GLOBALS['y'] = $GLOBALS['x'] + $GLOBALS['y'];
}

myTest();
echo $y; // outputs 15?>

PHP The static Keyword

Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job.

To do this, use the static keyword when you first declare the variable:

Example 1:

<?php
function myTest() {
    static $x = 0;
    echo $x;
    $x++;
}

myTest();
myTest();
myTest();
?>