PHP: Hypertext Preprocessor

This page summarizes Hypertext Preprocessor (PHP), a server-side HTML embedded script language like PERL (Practical Extraction and Report Language).

PHP BASICS

PHP is casesensitive. Each command ends with semi-colon (;).
The script begins with "<?php" and ends with "?>"
The // or # is used for single-line comments, while /* */ is generally used for comments in PHP.

GENERAL RESOURCES

http://www.php.net | Manual | Manual (Kr) | Downloads | FAQ
Zend.com | Manual | PHP Basics (IU) | phpMyAdmin
http://www.koreaphp.co.kr/ | www.phpschool.com/
http://www.perl.com | Matt's CGI Script | ALT PHP FAQ | IBM PHP Resources
Meta Tag Analyzer | HappyCGI | AcroEdit (Text Editor)

REGULAR EXPRESSION

Variables

Predefined Variables (e.g., $_SERVER)
$int=3; float=3.14; $str="Name"; $bool=TRUE;
$x=int; $y=SQR($x);
echo gettype($int); echo is_int($int); echo is_string($str);
define("PI", "3.14"); echo PI; // definition of a constant
is_null()

Array

$grade=array(1,2,3,4); echo $grade[0];
$male=array("female"=>0, "male"=>1); $white=array(0=>"others" 1=>"white");
$score=array('Korean'=>95, 'Math'=>80);
unset($score["Korean"]); unset($score);
$computer=array("H/W"=>array("CPU", "RAM"), "S/W"=>array("OS"=>"Linux", "Appls"=>"Word"));
is_array()

Operators

Assignment: =, += (for numeric), .= (for string)
Arithmatic: +, - *, /, ^, %
Incrementing: $a++; ++$a; $b--; --$b;
Relational: ==, != or <>, <, <=, >, >=, === (identical), !===
$y=(empty($_GET['website'])) ? 'www.masil.org' : $_GET['website'];
Logical: && or and, || or or, !, xor
$str2=$str."Concatenate'; $str.="Concatenate";
$run=`ls -al`; echo "$run\n";
pointer: & /* &$var; */

Pattern Syntax

FUNCTIONS

String Functions

chr(); explode(); implode(); join();
echo(); print(); printf();
ltrim(); rtrim(); trim(); strtoupper(); strtolower()
str_repeat(); str_replace(); str_split();
strlen(); strpos(); strstr();
substr(); substr_count(); substr_compare(); substr_replace()
is_string(), is_null()

Mathematics Functions

abs(), floor(), ceil(), round()
exp(), pow(b, p), log(), log10(), sqrt()
sin(), cos(), tan()
max(), min()
rand()
ls_int(), is_float(), is_long(), is_real()
is_bool(), is_binary(), is_numeric()

Date Functions

date(); time();
gmdate(); getdate();
localtime(); mktime();

User-defined Functions

function F_name(argements) {
(statements);
return ...;
}

OBJECT AND CLASS

Class | Object

class C_name {
   (variable definition)

   function __construct() {
      (statements);
   }

   function F_name() {
      (statements);
   }
...
}

$instant = new C_name();
$instant->F_name();

class Child extends Parent {
   (variable definition)

   function __construct() {
      (statements);
   }

   function F_name() {
      (statements);
   }
...
}

NETWORK AND WWW

HTTP

Network | Http | Ftp
header(); setcookie(); setrawcookie();
setcookie ("log", $todate, time()+86400);
echo $HTTP_COOKIE_VARS['log'];

WWW

$key = $HTTP_POST_VARS['returned']
$ip_address=$HTTP_SERVER_VARS['REMOTE_ADDR'];
$domain_name=gethostbyaddr($ip_address);
$browser=$HTTP_SERVER_VARS['HTTP_USER_AGENT'];

$header=<<<EOD
... HTML scripts...
EOD;

print $header;

CONTROL STRUCTURES

The "break" and "continue" may be used in a loop to respectively end and resume execution.

if () {...}

if (score > 50) {
statemens;
}

if () {...} else {...}

if (condition) {
   statements;
} elseif (conditon) {
   statements;
} else {
   statements;
}

while () {...}

while (condition) {
statements;
}

while (condition) :
statements;
endwhile;

do {...} while ()

do {
statements;
} while (condition);

for () {...}

for (init; condition; step) {
   statements;
}

for ($i=1; $i<=100; $i++) :
   statements;
endfor;

for ($i=1; $i<=100; $i++) {
   statements;
}

foreach ($array as $value) {...}

foreach ($array as $value) {
echo $value;
}

while ( list($key, $value) = each($array) ) {
echo "The $key. --> $value \n";
}

switch () case

switch (condition) {
case value1:    statements;
   break;
case value2:    statements;
   break;
... default:    statements;
   break;
}

switch ($mode) :
case 1:    ...;
endswitch;

switch ($week) {
case "Monday":    ...;
}

File Handling (IO)

File Handling

basename($path); dirname()
chmod(); fileperms();
copy(); delete(); mkdir(); rename(); rmdir();
disk_free_space(); disk_total_space();
file(); feof(); file_exists()
fileatime(); filectime(); filemtime(); filesize(); filetype();
fread(); fclose(); fputs(); fwrite(); fopen();

Reading Files

require 'header.php';
require('header.php');
require $external_file;
include 'header.php';

$file = "message.txt";
$fb = fopen($file,'a+');
$content = fread($fb,filesize($file));
fclose($fb);
$record = explode("\t",$content);
$total = intval($record[0]);

Writing Files

$file = "message.txt";
$fb = fopen($file,'w');
fwrite($fb, $text);
fclose($fb);

There are eight modes of file openning: "r" and "r+" for reading, "w" and "w+" for writing, "a" and "a+" for appending, and "x" and "x+" for creating and writing. "r" places file pointer at the beginning of the file, while "a" locate the pointer at the end of file.

MYSQL CONNECTION

MySql Connection

MySql Function | PDO_MYSQL | MySql Extension

$conn = mysql_connect('host', 'id', 'pw')
or die('Error: ' . mysql_error());
mysql_select_db('database', $conn)
or die('Connection failure');
...
mysql_close($conn);

Running Queries

$sql = 'SELECT a AS id, b, c FROM student WHILE c>=90';
$db = mysql_query($sql, $conn) or die('Query failure');
$record_num = mysql_num_rows($db);

while ( list($id, $name, $score) = mysql_fetch_array($db) ) {
echo "$id $name $score \n";
}