PHP(一)EnvironmentandTypes

PHP(1)Environment and Types
PHP(1)Environment and Types

1. Rebuild my win7 PHP environment
Download the latest version of PHP eclipse
http://mirror.cc.columbia.edu/pub/software/eclipse/technology/epp/downloads/release/helios/SR2/eclipse-php-helios-SR2-win32-x86_64.zip

Download the apache 2.2.21 version of windowns binary
http://mirrors.sonic.net/apache//httpd/binaries/win32/httpd-2.2.21-win32-x86-no_ssl.msi

Download the php source code
http://us.php.com/distributions/php-5.3.8.tar.gz
http://windows.php.com/downloads/releases/php-5.3.8-Win32-VC9-x86.zip
http://windows.php.com/downloads/releases/php-5.2.17-Win32-VC6-x86.zip

Install apache2.2.21

unzip php file php-5.3.8-Win32-VC9-x86.zip to the local dirver D:\tool\php-5.3.8
configure the apache configuration file httpd.conf

LoadModule php5_module "d:/tool/php-5.3.8/php5apache2_2.dll"
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps
Action application/x-httpd-php "d:/tool/php-5.3.8/php-cgi.exe"
AddType application/x-httpd-php .html
AddType application/x-httpd-php .htm
AddDefaultCharset UTF8
PHPIniDir "d:/tool/php-5.3.8"

create and change the php.ini file according to my php blog before. Make one file index.php to the htdoc directory of apache.
Visit this page http://localhost/index.php, everything is fine till now.

And I will configure this php environment work with eclipse php version according to my prevous blogs.

But this time, I directly change the directory to
DocumentRoot "C:/Users/Digby/workspace_php"

2. PHP grammer review


3. Types
Arrays
An array can be created by the array() language construct. It takes as parameters any number of comma-separated key => value pairs.
The key can only be an integer or string, value may be any value of any type.

$arr = array("foo" => 1, 12 => true);
echo gettype($arr[12]) . "
";
echo $arr[12];

output:
boolean
1

If a key is not specified for a value, the maximum of the integer indices is taken and the new key will be that value plus 1. If a key that already has an assigned value is specified, that value will be overwritten.

$arr = array(6 => 3, 5 => 4, 5, 6, "b" => 12, 6 =>100 );
echo $arr[6] . "
";
echo $arr[5] . "
";
echo $arr[7] . "
";
echo $arr[8] . "
";

output:
100
4
5
6

Creating/modifying with square bracket syntax
$arr = array(5 => 1, 12 => 2);
$arr[] = 56;
// This is the same as $arr[13] = 56;
// at this point of the script
$arr["x"] = 42;
// This adds a new element to
// the array with key "x"
echo $arr[13] . "
";
unset($arr[5]); // This removes the element from the array
unset($arr); // This deletes the whole array
if (NULL == $arr){
echo "empty arr!";
}
?>

As mentioned above, if no key is specified, the maximum of the existing integer indices is taken, and the new key will be that maximum value plus 1.

// Create a simple array.
$array = array(1, 2, 3, 4, 5);
print_r($array);
echo "
";
// Now delete every item, but leave the array itself intact:
foreach ($array as $i => $v) {
unset($array[$i]);
echo "unset $i => $v" . "
";
}
print_r($array);
echo "
";
// Append an item (note that the new key is 5, instead of 0).
$array[] = 6;
print_r($array);
// Re-index:
$array = array_values($array);
$array[] = 7;
echo "
";
print_r($array);

output:
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
unset 0 => 1
unset 1 => 2
unset 2 => 3
unset 3 => 4
unset 4 => 5
Array ( )
Array ( [5] => 6 )
Array ( [0] => 6 [1] => 7 )

Useful functions
The unset() function allows removing keys from an array. Be aware that the array will not be reindexed.

The array_values() function can be used to 'remove and shift'.
$a = array(1 => 'one', 2 => 'two', 3 => 'three');
unset($a[2]);
/* will produce an array that would have been defined as
$a = array(1 => 'one', 3 => 'three');
and NOT
$a = array(1 => 'one', 2 =>'three');
*/
print_r($a);
echo "
";
$b = array_values($a);
// Now $b is array(0 => 'one', 1 =>'three')
print_r($b);

Array do's and don'ts
$foo[bar] is wrong, but $foo['bar'] is right. This does not mean to always quote the key. Do not quote keys which are constants or variables, as this will prevent PHP from interpreting them.

examples:
$arr = array('fruit' => 'apple', 'veggie' => 'carrot');
// Correct
print $arr['fruit']."
"; // apple
print $arr['veggie']."
"; // carrot
// This defines a constant to demonstrate what's going on. The value 'veggie'
// is assigned to a constant named fruit.
define('fruit', 'veggie');
// Notice the difference now
print $arr['fruit']."
"; // apple
print $arr[fruit]."
"; // carrot

//it's inside a string. Constants are not looked for within strings
print "Hello $arr[fruit]
";

//braces surrounding arrays within strings allows constants
//to be interpreted
print "Hello {$arr[fruit]}
"; // Hello carrot
print "Hello {$arr['fruit']}
"; // Hello apple

references:
http://sillycat.iteye.com/blog/731677
http://sillycat.iteye.com/blog/768664
http://sillycat.iteye.com/blog/769110
http://sillycat.iteye.com/blog/770369