php h ypertext p re-processor. unit 6 - php - hello world! - data types - control structures -...
TRANSCRIPT
PHPPHP
Hypertext
Pre-processor
Unit 6 - PHP
- Hello World!- Data types- Control structures- Operators
Why do we need PHP?
● Dynamic data-driven web sites– Display dynamic information to users– Collect information from users
● Examples:– Online shopping site– Web forum– Newspaper site– etc
Options
● Perl● Microsoft ASP.NET● JSP● ColdFusion● XSLT● others
PHP Strengths
● High Performance● Interfaces with many database systems● Built-in libraries● Low cost● Open source● Support● Easy to learn and use
What is PHP?
● Server-side scripting language● Conceived in 1994● Open Source● Current version is 5● Reference page: http://www.php.net
How to use this lecture
● Just listen to it● You won’t remember everything – that’s
ok. That’s normal.● Ask questions if they occur to you.● Refer back to this presentation if you
need to.● Or refer to: http://www.php.net
How it works
● Client requests document● Server loads document in memory● Server processes document with
relevant module (PHP)● Server sends HTML document to client● Client displays document
Hello World!
Hello World!<html><body>
</body></html>
Hello World!
Output
Hello World!
Hello World!<html><body>
</body></html>
<?php ?> echo 'Hello World';
Output 1<html><body>
Hello World</body></html>
Output 2
Hello World
Hello World!<html><body> <?php echo "<p><i>Hello</i> <b>World</b></p>" ?>
</body></html>
Output 1<html><body>
<p><i>Hello</i> <b>World</b></p></body></html>
Output 2
Hello World
PHP Basics
PHP Syntax basics
● PHP code embedded in <?php … ?>● Files containing PHP code must have a .php extension (or
php3, etc)● Syntax very similar to C and Java
– Statements delimited by ;– Comments as in C/Java:
● /* comment */● // comment
– But also: # comment● Variables preceded by $, for example:
– $x = 2;– $first_name = joe;
● More on variables later …
Data Types
Data types
● Integer – for whole numbers● Float – for real numbers● String – for strings of characters● Boolean – for true or false values● Array – For collections of data● Object – For OO programming
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo $first_name;
Output:John
Strings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo '$first_name';
Output:$first_name
Strings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo "$first_name";
Output:John
Strings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo "Your name is: $first_name $last_name";
Output:Your name is: John Doe
StringsStrings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo "You said: \"my name is $first_name $last_name\"";
Output:Your said: “my name is John Doe”
StringsStringsStrings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo "... And you are worth \$2M";
Output:... And you are worth $2M
StringsStringsStringsStrings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo $first_name[0];
Output:J
StringsStringsStringsStringsStrings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo substr('abcdef', 1, 4);
Output:bcde
StringsStringsStringsStringsStringsStrings
<?php
?>
Strings
$first_name = 'John';$last_name = 'Doe';
echo substr($first_name, 0, 6);
Output:? (guess and write it down)
Strings
● No / Single / Double quote● String type:
http://uk.php.net/manual/en/language.types.string.php
● Functions available: http://uk.php.net/strings
Integers and Floats
<?php$a = 1234;$b = 12.02;
?>
● Integer type: http://uk.php.net/manual/en/language.types.integer.php
● Float type: http://uk.php.net/manual/en/language.types.float.php
Boolean
● Logical operators:– And: &&– Or: ¦¦– Not: !
● Boolean type: http://uk.php.net/manual/en/language.types.boolean.php
Array
id First Name Last Name Job
1 Joe Smith Surgeon
2 John Johnson Nurse
3 Jack Jackson Consultant
4 Jim Jones IT
Array
• Fundamental data structure in PHP• Used to store collections of values• Multidimensional array: array that
contains arrays.• Different types of arrays:
1. Numerically indexed arrays2. Non-numerically indexed arrays3. Does it make any difference?
1. Numerically indexed array
<?php$names = array( );
?>
'Joe','John','Jack','Jim'
echo $names[1];
Output:John
2. Non-numerically indexed array
<?php$record = array(
?>
firstName => 'John',lastName => 'Smith');echo $record[lastName];
Output:Smith
3. Key-value pairs
<?php$arr = array(
);echo $arr[1];
?>Output:…
0 => 'Joe',1 => 'John',2 => 'Jack',3 => 'Jim'
Multidimensional arrays
<?php$record = array(
);
/* i.e. an array of arrays */
array(firstName => 'Joe', lastName => "McDonald"),
array(firstName => 'John', lastName => "Smith"),
array(firstName => 'Jack', lastName => "Black")
Multidimensional arrays
...echo $record[1][lastName];echo '<br/>';echo $record[1][1];?>
Output:…
Operators
Directed studyhttp://uk.php.net/manual/en/language.operators.php
Control structureshttp://uk.php.net/manual/en/language.control-structures.php
if, else, elseif
<?php$value = 24;
?>
if ($value < 20) echo “not enough!”;
elseif ($value < 30) echo “reasonable.”;
elseif ($value < 40) echo “perfect!”;
else echo “Too much!”;
switch
<?phpswitch ($value){
}?>
case 24: echo "Correct!"; break;case 25: echo "Almost correct!"; break;default:
echo "Too much!";
for
<?php for ( ; ; ) {
}?>
($i = 1 $i <= 10 $i++
echo $i;
Output:12345678910
foreach
<?php
?>
$arr = array("one", "two", "three");
echo "Using a for loop:<br />\n";
for ($i = 0; $i < sizeof($arr); $i++) {
echo "Value: $arr[$i]<br />\n";
}echo "Using a foreach loop:<br />\n";
foreach ($arr as $value) {
echo "Value: $value<br />\n";
}
while
<?php
$i = 1;while ($i <= 10) { echo $i; i++;
} Output:12345678910
Summary
● Basics● Data types● Control structures● Operators - Directed study:
– Arithmetic operators– Comparison operators– Logical operators– String operators
http://uk.php.net/manual/en/language.operators.php