SYST 28043 Web Technologies SYST 28043 Web Technologies Intro to PHP

SYST 28043

Web Technologies

SYST 28043

Web Technologies

Intro to PHP

04/18/23 Wendi Jollymore, ACES 2

PHPPHP

PHP: Hypertext PreprocessorA recursive acronym

Currently on version 5.4.4http://www.php.netDeveloped as a set of “Personal Home page Tools”

Rasmus LerdorfSmall scripts to do things like track visitorsEventually became the PHP we know today


PHP - AdvantagesPHP - Advantages

Free, Open SourceFastRuns on most operating systemsEasy to learn – has C/Java/Perl type of syntaxLoosely-typedProcedure-oriented or object-orientedPowerful string processing and regular expression librariesVery large and active developer community


Testing PHPTesting PHP

See Notes for this lesson, “Testing PHP”1. Make sure your web server is running!2. Open a new PHP Project in Aptana


PHP SyntaxPHP Syntax

<?php /* all your php code here */?>

The <?php ?> tags contain the php codeAll executing statements end in a semi-colonYou can put your entire page in the tagsYou can embed the PHP throughout your XHTML code

See examples in the notes


PHP SyntaxPHP Syntax

Echo statementSends output to the pageDouble-quotes and single-quotes mean different thingsYou can use escape sequences like \n


PHP ExamplePHP Example

echo "<h3>This is a PHP Page by Kaluha</h3>";

echo "Today I'm beginning to learn some PHP. I'm liking it so far!";

echo "<hr>";

echo "Email me at <a href=\"mailto:[email protected]\">

[email protected]</a>! ";



Load the page in your browserView the browser source!Use the \n sequence to break up long lines

Makes browser source easier to read

Add the \n to your code statements and reload



Add this:echo "Current Date and Time: ";

echo date("l jS \of F Y h:i:s A");

echo "\n";

Do the date() exercise in the notes


PHP CommentingPHP Commenting

Single-line comments can start with // or ## this is a comment

// this is a comment

Multi-line comments can be enclosed in /* and *//* this is a multi-

line comment.

*/


IdentifiersIdentifiers

Rules for Identifiers:identifier names are case-sensitiveidentifiers must start with a letter or underscore characteridentifier names may not contain spacesidentifiers must be made up of letters and numbers and symbols from ASCII 127 to ASCII 255


VariablesVariables

Called “scalars”You don’t have to declare variables

But you can

To declare a variable, just initialize it:

$userName="";

$dateFlag = 1;


VariablesVariables

ScalarsVariables that hold a single valueAlways starts with a $Value can be one of:

BooleanTrue or falseFalse = 0; any other integer is true

IntegerFloating-pointstring


ConstantsConstants

Constants are declared using the define() method:define(“PST_RATE”, .08);

Defines a constant called PST_RATE with an initial value of .08Use it just like you would use any other scalar:

$pstAmt = $subTotal * PST_RATE;


Escape SequencesEscape Sequences

\b backspace

\f Form feed

\n New-line

\r Carriage return

\t Tab

\’ Single-quote

\” Double-quote

\\ Backslash


OperatorsOperators

Arithmetic Operators+ addition- subtraction* multiplication/ division% modulus

Pre- and post- unary operators:++ unary increment -- unary decrement


OperatorsOperators

Assignment Operators= equals+= plus-equals-= minus-equals*= multiply-equals/= divide-equals%= modulus-equals


OperatorsOperators

Relational Operators== equal to!= not equal to> greater than>= greater than or equal to< less than<= less than or equal to

Logical Operators&&, AND AND Operator||, OR OR Operator! , NOT NOT Operator


OperatorsOperators

String Operators . Concatenation operator .= Assignment-Concatenation

Examples:echo “Value: “.$value.”\n”;

$value .= $newValue;


OperatorsOperators

Conditional Operatorcondition ? retValueTrue : retValueFalse;If condition is true, retValueTrue is returnedIf condition is false, retValueFalse is returned

Example:$validNum = ($intValue > 0) ? “valid” : “invalid”;


String InterpolationString Interpolation

Double-Quotes:Variables and escape sequences are parsedExample:

$catName = "Mr. Bibs";echo "Wendi's cat's name is $catName.\nThis is a new line.";

Output:Wendi's cat's name is Mr. Bibs.This is a new line.

Browser Source:Wendi's cat's name is Mr. Bibs.This is a new line.



Single-Quotes:Variables and escape sequences are not interpreted, except where it might cause a syntax errorExample:

echo 'My variable is $catName and it\'s \n case-sensitive.';

Output:My variable is $catName and it's \n case-sensitive.



Heredoc:Using labels to mark larger passages of textContent between labels is interpreted as if in double-quotes

But you don’t have to escape double-quotes

Starting and ending labels must matchLabels must be in upper-caseStarting label must be preceeded by <<<Ending label must be first on a blank line

Not even spaces in front of it



Heredoc Example:<?php

$website = "http://www.thinkgeek.com";

echo <<<GEEK

One of my favourite web sites is <a href = "$website">Thinkgeek.com</a>. This is a great site for geeks and coders because they have lots of caffeine products (drinks, candy, coffee mugs, etc) and lots of what they refer to as Cube Goodies. Cube goodies are little toys that keep you amused in your office cube.

GEEK;

?>


Control StructuresControl Structures

If-Statementsif (condition){

// code body

}

if (condition){

// code body

} else {

// code body

}


ExerciseExercise

Do the Tip Calculator exercise in the notesPass the input values using GET method name=value pairsE.g.

localhost/webtech/projetName/ex1.php?billAmt=35.55&tipPercent=15


IterationIteration

Pre-Test and Post-Test Loop

while(condition) {

// code body

}

do {

// code body

} while (condition);


IterationIteration

For Loops:

for (init; condition; cont) {

// code body

}

foreach (item as collectionType) {

// code body

}


ExercisesExercises

Do the Multiplication Table exercise in the notes


ArraysArrays

Arrays in PHP work similarly to arrays in other languages

Arrays are 0-based by defaultArray elements are identified with indexes or subscripts


Creating ArraysCreating Arrays

Using the array() function:$arrayName = array(value1, value2, value3, …);Example:

$languages = array(“Java”, “PHP”, “Perl”, “C#”, “Visual Basic”);

Creates an array called $languages with 5 elements (indexed 0 to 4)


Creating ArraysCreating Arrays

Hard coding the arrays$languages[0] = “Java”;

$languages[1] = “PHP”;

…

You can actually do this without the indexes:

$languages[] = “Java”;

$languages[] = “PHP”;

Indexes will default 0, 1, 2..


Iterating Through ArraysIterating Through Arrays

Foreach loop:foreach($arrayName as $arrayElement) {

// code

}

Example:foreach($languages as $aLang) {

echo $aLang.” ”;

}


Length of ArraysLength of Arrays

count() function:

foreach($grades as $g) {

$totalGrade += $g;

}

$avg = $totalGrade / count($grades);

echo "Average Grade: ".$avg;


Associative ArraysAssociative Arrays

Elements consist of a key and value pair

The key is the indexThe value is the content of the array element

Keys must be uniqueKeys can be strings

E.g. $grades[“prog10082”] = 75;



Creating an associative array:$myGrades = array("PROG10082" => 89.5, "PROG24178"

=> 85.0, "INFO16029" => 91.5, "SYST13416" => 80.5);

$myGrades array contains 4 elements

“PROG10082” 89.5

“PROG24178” 85.0

“INFO16029” 91.5

“SYST13416” 80.5



Using foreach() with associative arrays:foreach(array_expr as $key => $value) { // statements}

Example:echo "My Grades: "; foreach($myGrades as $course => $mark) {echo “$course: ”;

echo “$mark \n”;}echo "\n";


Adding Array ElementsAdding Array Elements

Arrays in PHP are dynamicThe number of elements can change while the program executes

You can add elements to an array during run-time:

$languages[] = “Delphi”;

$myGrades[“SYST28043”] = 79.1;


Adding Array ElementsAdding Array Elements

array_push($arrayName, $element) functionAdds an element to the end of an arrayYou can add multiple elements:array_push($arrayName, $el1, $el2, $el3);

array_unshift($arrayName, $element) functionAdds an element to the beginning of an arrayYou can add multiple elements just as you can with array_push

array_push($languages, “Delphi”, “C++”);

array_unshift($languages, “COBOL”);


Removing Array ElementsRemoving Array Elements

$element = array_pop($arrayName) function

Removes the last element and returns it

$element = array_shift($arrayName) function

Removes the first element and returns it

$lastEl = array_pop($languages);

$firstEl = array_shift($languages);


Array ExercisesArray Exercises

Do the array exercises in the notes.


Next Class:Next Class:

FunctionsVariable ScopeForm ProcessingForm Validation

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SYST 28043 Web Technologies SYST 28043 Web Technologies Intro to PHP