PHP Teresa Worner

What is it? PHP: Hypertext Preprocessor server-side scripting language open source cross-platform compatible with almost all servers.php.php3.phtml

Installing PHP XAMPP – MySQL, PHP, Perl – C:\xampp\htdocs –

Embedding in HTML begin/end with tags <?php... ?> PHP parser ignores code outside PHP code run on server, result sent to client as HTML

Basic Syntax semicolons comments // single line comment # also a single line comment /* multi-line comment */ **Note: single line comments end at the end of the line OR at the closing PHP tag – whichever comes first!

Basic Syntax Cont’d if statements if ($var) //one line elseif ($var2) //one line else //one line print to screen echo “text”; if ($var) { //multi-line } else { //multi-line } if ($var): //multi-line else: //multi-line endif;

Variables $variableName – after $, must begin with letter or underscore, then any length of numbers/letters/underscores predefined variables – examples: $_POST[“name”] $_GET[“name”] $_FILES[“name”]

Constants define(“constName”, assignment) do not begin constName with $ bool, int, float, string

Types //loosely typed $var1 =“0”; $var1 += 2; //$var1 is now an integer of value 2 $var1 += 1.3; //$var1 is now a float of value 3.3 $var1 += “10 people”; //$var1 is float of value 13.3 $var1 += “hi”; //$var1 is float of value 13.3 $var2 = array(key => value, key2 => value2, );

Operators arithmetic, assignment, bitwise like C++ comparison $a == $b //true if $a equals $b after type juggling $a === $b //true if $a equals $b and same type $a != $b //not equal after type juggling $a <> $b //not equal after type juggling $a !== $b //not equal and not same type // =

Operators Cont’d Logical $a and $b $a && $b $a or $b $a || $b $a xor $b ! $a string $a. $b //concatenation

Operators Cont’d array $a + $b //union of $a and $b $a == $b //true if $a and $b have same key/value pairs $a === $b //same key/value pairs, order, and types $a != $b //not equal $a <> $b //not equal $a !== $b //not identical

Functions many built-in functions: user declared: function funcName($var1, $var2) { return $var1 + $var2; }

Sessions session_start – starts or resumes session – default setting saves session ID in cookie $_SESSION – superglobal array for session variables – $_SESSION[“variableName”] session_unset – frees session variables session_destroy – destroys session but does not free session variables or delete cookie

Other Stuff classes class ClassName {... } try-catch try {... } catch(Exception $e) {... }

Useful References