<?php
echo strlen("Hello world!"); // outputs 12
?>
<?php
echo str_word_count("Hello world!"); // outputs 2
?>
<?php
echo strrev("Hello world!"); // outputs !dlrow olleH
?>
<?php
echo strpos("Hello world!", "world"); // outputs 6. If no match is found, it will return FALSE.
?>
<?php
echo str_replace("world", "Dolly", "Hello world!"); // outputs Hello Dolly!
?>
<?php
define("GREETING", "Welcome to W3Schools.com!"); // syntax: define(name, value, case-insensitive)
echo GREETING;
?>
operation
=== $x === $y return true if $x is equal to $y, and they are of the same type
<> $x <> $y return true if $x is not equal to $y
!== $x !== $y return true if $x is not equal to $y, or they are not of the same
if (condition) {
code to be executed if this condition is true;
} elseif (condition) {
code to be executed if this condition is true;
} else {
code to be executed if all conditions are false;
}
e.g:
<?php
$t = date("H");
if ($t < "10") {
echo "Have a good morning!";
} elseif ($t < "20") {
echo "Have a good day!";
} else {
echo "Have a good night!";
}
?>
foreach ($array as $value) {
code to be executed;
}
e.g:
<?php
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $value) {
echo "$value <br>";
}
?>
<?php
function setHeight($minheight = 50) {
echo "The height is : $minheight <br>";
}
setHeight(350);
setHeight(); // will use the default value of 50
setHeight(135);
setHeight(80);
?>
<?php
$cars = array("Volvo", "BMW", "Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
?>
<?php
$cars = array("Volvo", "BMW", "Toyota");
echo count($cars); //output 3
?>
PHP Associative Arrays:associative arrays are arrays that use named keys that you assigin to them
<?php
$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>
<?php
$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
foreach($age as $x => $x_value) {
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>
Sort Funcitions For Arrays
sort() -- sort arrays in ascending order
rsort() -- sort arrays in descending order
asort() -- sort associative arrays in ascending order, according to the value
ksort() -- sort associative arrays in ascending order, according to the key
arsort() -- sort associative arrays in descending order, according to the value
krsort() -- sort associative arrays in descending order, according to the key
Superglobals: PHP Global Variables
Several 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 PHO superglobal variables are:
$GLOBALS $_SERVER $_REQUEST $_POST $_GET $_FILES $_ENV $_COOKIE $_SESSION
<?php
echo $_SERVER['PHP_SELF']; // Returns the filename of the currency executing script
echo "<br>";
echo $_SERVER['SERVER_NAME']; // Returns the IP address of the host server
echo "<br>";
echo $_SERVER['HTTP_HOST']; // Returns the host header from the current request
echo "<br>";
echo $_SERVER['HTTP_REFERER']; // Returns the complete URL of the current page
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME']; // Return the URI of the current page
?>
$_SERVER['GATEWAY_INTERFACE'] returns the version of the Common Gateway Interface the server is using
$_SERVER['SERVER_ADDR'] returns the IP address of the host server
$_SERVER['SERVER_SOFTWARE'] returns the server identification string
$_SERVER['SERVER_PROTOCOL'] returns the name and reversion of the information protocol
$_SERVER['REQUEST_METHOD'] return the request method used to access the page
$_SERVER['QUERY_STRING'] return the query string if the page is accessed via a query string
$_SERVER['HTTP_ACCEPT'] return the Accept header from the current request
$_SERVER['HTTPP_ACCEPT_CHARSET'] return the Accept_Charset header from the current request
$_SERVER['HTTP_HOST'] return the host header from the current request
$_SERVER['HTTP_REFERER'] return the complete URL of the current page
$_SERVER['HTTPS'] is the script queried through a secure HTTP protocol
$_SERVER['REMOTE_ADDR'] return the IP address from where the user is viewing the current page
$_SERVER['REMOTE_HOST'] return the host name from where the user is viewing the current page
$_SERVER['REMOTE_PORT'] return the port being used on the user's machine to communicate with the web server
$_SERVER['SCRIPT_FILENAME'] return the absolute pathname of the currently executing script
$_SERVER['SERVER_ADMIN'] return the value given to the SERVER_ADMIN directive in the web server configuration file
$_SERVER['SERVER_PORT'] return the port on the server machine being used by the web server for communication
$_SERVER['SERVER_SIGNATURE'] return the server version and virtual host name which are used by the web server for communication
$_SERVER['PATH_TRANSLATED'] return the file system based path to the current script
$_SERVER['SCRIPT_NAME'] return the path of current script
$_SERVER['SCRIPT_URI'] return the URI of the current page
PHP $_REQUEST is used to collect data after submitting an HTML form
<html>
<body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// collect value of input field
$name = $_REQUEST['fname'];
if (empty($name)) {
echo "Name is empty";
} else {
echo $name;
}
}
?>
</body>
</html>
PHP $_POST is used to collect form data after submitting an HTML form with method = "post",$_POST is also widely used to pass variables
<html>
<body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// collect value of input field
$name = $_POST['fname'];
if (empty($name)) {
echo "Name is empty";
} else {
echo $name;
}
}
?>
</body>
</html>
PHP $_GET is used to collect form data after submitting an HTML form with method="get".$_GET can also collect data sent in the URI
<html>
<body>
<?php
echo "Study " . $_GET['subject'] . " at " . $_GET['web'];
?>
</body>
</html>