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.net/distributions/php-5.3.8.tar.gz
http://windows.php.net/downloads/releases/php-5.3.8-win32-vc9-x86.zip
http://windows.php.net/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
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