Learning PHP

Learning
php

What Php
can do

server-side scripting
command-line scripting
desk-top applications
interfacing with a database (most are supported in PhP)
interfacing with LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM
Outputting images, pdf files, etc.

PHP Documentation

basic syntax

PHP used for server-side scripting is typically embedded in XHTML code but the file is named with a php extension.

The extension php on the filename signals that the PHP interpreter should be executed to process the file before it is sent to the end-user.

The interpreter only executes the statements between the beginning php tag <?php and the ending php tag ?>. The rest of the text(XHTML) in the file is simply written as-is to the file that will be sent to the end-user.

PHP is case-sensitive.

PHP statements end with a semi-colon ;

PHP uses the curly braces { } to block statements.

Basic embedded php syntax:

<?php
.... php statements to execute
?>

Creating your first
php script

Try This:

Create the following php script in notepad:

<html>
<head>
<title>PHP Test</title>
</head>
<body>

<?php
print ("Hello world\n");
?>

</body>
</html>

Save the file as php_ex1.php

Upload it to Linux

Open the file using Internet Explorer

View source

Edit the file -> change the print statement to

print (" <h1>Hello world</h1> \n");

Save the file as php_ex2.php

Upload it to Linux

Open the file using Internet Explorer

View source

variables

Data types:

Four scalar types:

boolean
integer
float (floating-point number, aka 'double')
string (double or single quotes)

Two compound types:

Variables are typically not typed but the data type is determined at runtime.

Variable names:

start with a dollar sign, followed by a valid PHP identifier.
The PHP identifier could be a field name from a form or a field of a table in a database table.

PHP identifier:

alphabetic or underscore, followed by alphanumeric or underscore

Simple
selection statement

if (exp)
statement;

if-else

if (exp)
statement;
else
statement;

if-elseif

if (exp)
    statement;
elseif (exp)
    statement;
elseif (exp)
    statement;
else
    statement;

Creating your first
script to process a
form

You will need the pet form created in the form lecture: petform

Make sure the petform submit action sends it to your petform_ex1.php script

Try This:

The script should send a page back to the end user - recapping the info from the pet form.

Create the following php script in notepad:

<html>
<head>
<title>Pet Form Response</title>
</head>
<body>

<?php
print(" The name of your pet is $petname \n");
print(" The owner of your pet is $petowner \n");

?>

</body>
</html>

Save the file as petform_ex1.php

Upload it to Linux

Open the petform_ex1.htm using Internet Explorer

Fill in the information and submit the form

View source

Edit the file -> add the processing for gender and pettype

if ($pettype == 1)
 print(" You own a dog! \n\n");
elseif ($pettype == 2)
 print(" You own a cat! \n\n");
elseif ($pettype == "3")
 print(" You own a hamster! \n\n");
elseif ($pettype == "4")
 print(" You own a fish! \n\n");
elseif ($pettype == "5")
 print(" You own a bunny! \n\n");

if ($gender == "male")
 print(" Your pet is male \n\n");
else
 print(" Your pet is female \n\n");

Save the file as petform_ex1.php

Upload it to Linux

Open the petform_ex1.htm using Internet Explorer

Fill in the information and submit the form

View source

loops

while

while (exp)
statement;

do-while

do
{
statement;
} while (exp);

for

for (exp1; exp2; exp3)
statement;

foreach

- used only for arrays as a way to iterate through the array

foreach (array_exp as $value)
statement

- will iterate through the array given in the array_exp assigning the array value to $value

foreach (array_expression as $key => $value)
statement

- will iterate through the array given in the array_exp assigning the array value's key to $value

processing a
checkbox

Try This:

edit the file petform_ex1.php -> add the processing for petstuff

if (count($petstuff)>0)
 foreach($petstuff as $value)
 {
 print(" Your pet is $value \n\n");
 }

Save the file as petform_ex1.php

Upload it to Linux

Open the petform_ex1.htm using Internet Explorer

Fill in the information and submit the form

View source

the php example from class: click here