Svetoslav Marinov’s Blog

On my development machine which runs Fedora code 8 used to prompt me every once in a while for password. This is very annoying but secure

Here are the steps how to disable that screen saver password prompt

Click "K" > Control Center > Appearance & Themes > Screen Saver

Under Settings uncheck "Require password to stop"

Related

• http://www.databook.bz/?page_id=219
• http://forum.soft32.com/linux/disable-inactivity-screen-lock-Fedora-Core-ftopict357046.html

[code]
perl -MCPAN -e shell

o conf urllist push ftp://ftp-mirror.internap.com/pub/CPAN/
o conf commit

[/code]

I've been always wondering how to get the first element of an associative array in PHP.
For numeric keys you could just do $arr[0] but it'll a little bit different for associative arrays.

Solutions

[code]
$arr = array('one' => 'hello', 'two' => 'world');
[/code]

Solution #1
[code]
reset($arr);
list ($key1, $val1) = each($arr);
[/code]

Solution #2
[code]
$i = 0;
foreach ($arr as $key => $value) {
if (++$i == 1)
echo $key;
break;
}
}
[/code]

Solution #3
[code]
reset($arr);
echo key($arr);
[/code]

Solution #4
[code]
reset($arr);
echo @array_shift(array_keys($arr));
[/code]

Suppressing Warnings such as:
Debug Strict (PHP 5): PHPDocument1 line 6 - Only variables should be passed by reference

Solution #5
[code]
reset($arr);
echo end(array_keys(array_reverse($arr)));
[/code]

Most of solutions can be found on http://www.webmasterworld.com/forum88/3811.htm

Related

• http://tech.petegraham.co.uk/2007/05/15/php-get-first-index-in-associative-array/

Can you come up other solutions ?
Feel free to share your experience by commenting this posting below.

Many times we need just the total number of rows that are produced by a single SELECT statement.
If you have even just a little experience with MySQL or other database(s) you'll think of COUNT(*) or similar function.

The query below uses COUNT(*) function but does not return the total number of rows.
It actually returns how many orders each customer has made.
When a query contains GROUP BY clause the situation changes.

[code]
mysql> SELECT c.*, COUNT(c.id) as cnt FROM `test_orders` AS o INNER JOIN test_customers AS c ON o.customer_id = c.id GROUP BY c.id;
+----+-----------+------------------------+-----+
| id | cust_name | cust_email | cnt |
+----+-----------+------------------------+-----+
| 1 | Slavi | slavi at slavi dot biz | 2 |
| 2 | Test | test at test dot com | 1 |
+----+-----------+------------------------+-----+
2 rows in set (0.00 sec)
[/code]

What if we want to create a pagination ?
Then we'll need to calculate the total number of rows for this query.

Solutions:
#1 Putting the main query into a subquery

[code]
SELECT count(*) as total_rows FROM (SELECT c.*, COUNT(c.id) as cnt FROM `test_orders` AS o INNER JOIN test_customers AS c ON o.customer_id = c.id GROUP BY c.id) as tab
[/code]

#2 Using MySQL's SQL_CALC_FOUND_ROWS and performing a second query
[code]
SELECT SQL_CALC_FOUND_ROWS c.*, COUNT(c.id) as cnt FROM `test_orders` AS o INNER JOIN test_customers AS c ON o.customer_id = c.id GROUP BY c.id LIMIT 10;
[/code]

[code]
mysql> SELECT SQL_CALC_FOUND_ROWS c.*, COUNT(c.id) as cnt FROM `test_orders` AS o INNER JOIN test_customers AS c ON o.customer_id = c.id GROUP BY c.id;
+----+-----------+------------------------+-----+
| id | cust_name | cust_email | cnt |
+----+-----------+------------------------+-----+
| 1 | Slavi | slavi at slavi dot biz | 2 |
| 2 | Test | test at test dot com | 1 |
+----+-----------+------------------------+-----+

mysql> SELECT FOUND_ROWS();
+--------------+
| FOUND_ROWS() |
+--------------+
| 2 |
+--------------+
1 row in set (0.00 sec)
[/code]

Note:
For "mysql>" is means that the commands are executing in a MySQL console.

Database Scheme

[code]
--
-- Table structure for table `test_customers`
--

CREATE TABLE `test_customers` (
`id` int(11) NOT NULL auto_increment,
`cust_name` varchar(255) NOT NULL,
`cust_email` varchar(255) NOT NULL,
KEY `id` (`id`,`cust_name`,`cust_email`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;

--
-- Dumping data for table `test_customers`
--

INSERT INTO `test_customers` (`id`, `cust_name`, `cust_email`) VALUES
(1, 'Slavi', 'slavi at slavi dot biz'),
(2, 'Test', 'test at test dot com');

-- --------------------------------------------------------

--
-- Table structure for table `test_orders`
--

CREATE TABLE `test_orders` (
`order_id` int(11) NOT NULL auto_increment,
`customer_id` int(11) NOT NULL,
`order_date` datetime NOT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

--
-- Dumping data for table `test_orders`
--

INSERT INTO `test_orders` (`order_id`, `customer_id`, `order_date`) VALUES
(1, 1, '2009-01-06 20:00:00'),
(2, 1, '2009-01-06 20:30:00'),
(3, 2, '2009-01-06 19:00:00');
[/code]

Related

• http://dev.mysql.com/doc/refman/5.1/en/counting-rows.html
• http://dev.mysql.com/doc/refman/5.0/en/information-functions.html
• http://www.mysqlperformanceblog.com/2007/08/28/to-sql_calc_found_rows-or-not-to-sql_calc_found_rows/

Sometimes arrays get filled with empty values and we need to remove them.
Here is a function that removes all empty values in an array.
The text is cleaned by HTML if any.

Notes:

1. There is not a check for duplicate elements.
2. This function may break UTF-8 strings.

[code]
$a[5] = 777;
$a[4] = array(
1 => 'test3',
2 => '',
3 => '',
4 => 'test2',
9 => 'test',
17 => '',
);
$a[9] = 'test';
$a[1] = 111;
$a[2] = 222;
$a[7] = '';
$a['axa'] = 'sfaf';
$a['axgga'] = '';
$a['gsdgsdg'] = 'sfaf';
[/code]

// Output
[code]
array(7) {
[0]=>
string(3) "777"
[1]=>
array(3) {
[0]=>
string(5) "test3"
[1]=>
string(5) "test2"
[2]=>
string(4) "test"
}
[2]=>
string(4) "test"
[3]=>
string(3) "111"
[4]=>
string(3) "222"
["axa"]=>
string(4) "sfaf"
["gsdgsdg"]=>
string(4) "sfaf"
}
[/code]

[code]
/**
* Removes empty values from an array. Also the numeric keys get reordered.
* If a value is an array the process of cleaning is repeated recursively.
* Elements start from 1 not from 0 if $non_zero_start is set to 1. Defaults to 0.
* Values are cleaned by HTML and also by leading/trailing whitespaces.
*
* @param array $arr
* @param bool $non_zero_start if 1 is supplied the array will start from 1
* @return array
* @author Svetoslav Marinov
* @copyright January 2009
* @license LGPL
*/
function cleanupArray($arr, $non_zero_start = 0) {
$new_arr = array();
foreach ($arr as $key => $value) {
if (!empty($value)) {
if (is_array($value)) {
$value = cleanupArray($value, $non_zero_start);

// If after the cleaning there are not elements do not bother to add this item
if (count($value) == 0) {
continue;
}
} else {
$value = trim(strip_tags($value));
if (empty($value)) {
continue;
}
}

$new_arr[$key] = $value;
}
}
// Reordering elements
if (!empty($new_arr)) {
if (!empty($non_zero_start)) {
$new_arr = array_merge_recursive(array("") + $new_arr);

// We don't need an empty first element.
// This was used to shift other elements to start from 1 instead of 0
unset($new_arr[0]);
} else {
$new_arr = array_merge_recursive($new_arr);
}
}
return $new_arr;
}
[/code]

Related:

• http://mistonline.in/wp/to-remove-an-empty-element-from-an-array-using-php/

I recently added my RSS feeds to FeedBurner .
Here is what is worked for me.

My blog is located in /blog directory you may need to change RewriteBase if your blog is installed in another directory. Additionally you'll have to change YOUR_BLOG_ID to match your provided by FeedBurner.

In the .htaccess rules we allow FeedBurner itself to retrieve the feeds otherwise there will be an infinite loop.
[code]
RewriteEngine On
RewriteBase /blog/

# Enable FeedBurner services
RewriteCond %{HTTP_USER_AGENT} !^(FeedBurner|FeedValidator)
RewriteRule ^feed http://feeds.feedburner.com/YOUR_BLOG_ID [R=307,L]
[/code]

Related

• http://codex.wordpress.org/Using_FeedBurner
• http://forums.feedburner.com/viewtopic.php?t=17