php - introduction week 5 dr. ken cosh introducing php 1
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PHP - IntroductionWeek 5
Dr. Ken Cosh
Introducing PHP
1
Introduction
• PHP : Hypertext Preprocessor
• Server-side script language
• Supported by Apache/IIS on various platform (MS/Linux/Mac OS)
• Opensource (PHP License v3.01)
2
Introduction – cont.
• Extension: .php
• File content
• Html code
• PHP code
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PHP
Request
HTML
Installation
• LAMP (or MAMP, or WAMP…)
• Testing
• Create a file and named it “test.php”
• The content is “<$php phpinfo(); $>”
4
Outline
• PHP Structure
• Comments, Syntax, Variables
• Operators
• Conditionals
• Looping
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Basic Syntax
• Script blockings start with <?php ?>
• Can be anywhere in the code
• It can be <? ?>
• Inside the block are html-code, php-code, or text
• Comment the code by // or /* */ as in C
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Basic Syntax
• Put the script in test.php<html><body><?php
echo “hello, world”;
?></body></html>
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Variables
• One type, just variables
• Can store numbers, strings, or array
• Conversion between type is automatically done.
• Variables begin with $, e.g. $var1 = 1; or $var2 = “alice”;
• No declaration is required.
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Variables
• Naming rules
• Begins with letter or _ (after $)
• Contains only A-Z, a-z, 0-9, and _
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Variables - Array
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Numeric $cars=array("Saab","Volvo","BMW","Toyota"); $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota";
Variables - Array
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Associative $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34); Or
$ages['Peter'] = "32"; $ages['Quagmire'] = "30"; $ages['Joe'] = "34";
Example,
<?php
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
echo "Peter is " . $ages['Peter'] . " years old.";
?>
Strings
• Functions• Concatenate: .
• Length: strlen()
• Search/Position: strpos(text, pattern)
• More information: http://www.w3schools.com/php/php_ref_string.asp
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Strings
• Put the script in test2.php<html><body><?php
$h1 = “hello”;$h2 = “world”; echo $h1.”, “.$h2.”<br/>”;echo “h1 has: “.strlen($h1).” letters in it <br/>”;
?></body></html>
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Operators - Arithmetic
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Operators - Assignment
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Operators - Comparison
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Operators - Logical
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Control Flow
• if/while/do…while/for• All the same as C.
• for each• Syntaxforeach ($array as $value) { code to be executed; }
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Control Flow
• Example<html><body>
<?php$x=array("one","two","three");foreach ($x as $value) { echo $value . "<br />"; }?>
</body></html>
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Form
• Put the script in test_form.php<html><body>
<form action="welcome.php" method="post">Name: <input type="text" name="fname" />Age: <input type="text" name="age" /><input type="submit" />
</form>
</body></html>
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Form
• Put the script in welcome.php<html><body>
Welcome <?php echo $_POST["fname"]; ?>!<br />You are <?php echo $_POST["age"]; ?> years old.
</body></html>
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Form
• Get, put the script in test_form.php<html><body>
<form action="welcome.php" method=“get">Name: <input type="text" name="fname" />Age: <input type="text" name="age" /><input type="submit" />
</form>
</body></html>
• http://localhost?fname=Peter&age=37
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Form
• Get• Visibility
• Though, it can be bookmarked
• Not suitable for large variables (>2000 characters)
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