PHP Cheat Sheet
Constants
<?php
define( "HOST_SITE", "www.pbwiki.com" );
echo HOST_SITE
?>
Results in www.pbwiki.com being printed
Strings
String values can be delimited using either single or double quotes. Single quotes allow a variable's value to be inserted inside a double quoted string.
e.g.
$firstName = "Bill";
$lastName = "Smith";
echo "First name is '$firstName' and last name is '$lastName'.";
// previous statement prints: First name is Bill and last name is Smith.
echo "First name is {$firstName} and last name is {$lastName}.";
// alternate syntax to previous statement that prints: First name is Bill and last name is Smith.
echo 'First name is "$firstName' and last name is "$lastName".';
// previous statement prints: First name is "$firstName" and last name is "$lastName".
The escape character is the back slash (e.g. $name = 'Tom\'s Automotive'; )
The concatenation character is the period (e.g. $firstName . ", " . $lastName; )
Arrays
Arrays don't have to be declared prior to use. The following is permitted:
$zipCodes[ 0 ] = '45239';
$zipCodes[ 1 ] = '07901';
$zipCodes[ 2 ] = '52100';
A short cut for the previous example is (notice missing array index numbers):
$zipCodes[ ] = '45239';
$zipCodes[ ] = '07901';
$zipCodes[ ] = '52100';
A second short cut for the previous example is:
$zipCodes = array( '45239' , '07901' , '52100' );
Arrays can also be indexed by key values:
$petName[ 'cat' ] = "sparky";
$petName[ 'dog' ] = "fido";
$petName[ 'snake' ] = "larry";
// Or, using shortcut syntax:
$petName = array( "cat" => "sparky" , "dog" => "fido" , "snake" => "larry" );
Printing Arrays
The following two commands print out slightly different dumps of the array:
print_r( $petName );
var_dump( $petName );
Sorting arrays
Sorting arrays with numeric indexes: sort( $zipCodes );
Sorting arrays with string indexes: asort( $petName );
Walking an array
foreach( $petName as $animal => $name ) {
// $animal is a variable that will contain the key and $name is a variable that will contain the value
echo "{$animal}'s name is {$name}";
}
foreach( $petName as $name ) {
// $name is a variable that will contain the value. The key is not used.
echo "name is {$name}";
}
Functions
Default parameter values
The following function allows for optional parameters, using defaults when parameters are missing:
function addNumbers( $firstVal = 1 , $secondVal = 2 ) {
return $firstVal + $secondVal;
}
echo addNumbers(); // prints 3 (uses default vals 1 and 2)
echo addNumbers( 5 ); // prints 7 (uses passed parm 5 and default val 2)
echo addNumbers( 5 , 10 ); // prints 15 (uses passed parms 5 and 10)
Sessions
Create a session (if one does not already exist)
Session variables
$_SESSION[ 'favColor' ] = "red"; // Saves session data
$lastPage = $_SESSION[ 'lastPage' ]; // Reads session data
PHP4 vs PHP5
PHP4
var statement
constructor named for the class
class person {
var $a;
function person() { }
}
PHP5
private, protected, public statement
constructor named __construct
class person {
private $a;
function __construct() { }
}
_uacct = "UA-3717444-1"; urchinTracker();
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