From Antispambot to Zeroize, WordPress has all sorts of lesser known or used functions. This presentation given at WordCamp Jerusalem 2013 goes over 10 such functions.

1. antispambot()
...
zeroize()

2. $ whoami

3. Yoav Farhi
Developer
blog.yoavfarhi.com
@yoavf

4. $ pwd

6. //antispambot()
/**
* Converts email addresses characters to HTML entities
* to block spam bots.
*
* @return string Converted email address.
*/
function antispambot($emailaddy, $mailto=0)
?>
Email me at:
<?php echo antispambot('yoav@farhi.org'); ?>
Email me at:
yo&#97;v&#64;&#102;a&#114;&#104;&#105;&#46;org

7. //checked(), selected(), disabled()
/**
* Outputs the html checked attribute.
*
* Compares the first two arguments and if identical
* marks as checked
*
* @return string html attribute or empty string
*/
function checked( $checked, $current = true, $echo = true )
?>
<input type='checkbox' name='postlink' value='1' <?php if
( 1 == $postlink ) echo 'checked="checked"'; ?> />
<input type="checkbox" name="postlink" value="1" <?php
checked( $postlink, 1 ); ?> />

8. //human_time_diff()
/**
* Determines the difference between two timestamps.
*
* The difference is returned in a human readable
* format such as "1 hour", * "5 mins", "2 days".
* @return string Human readable time difference.
*/
function human_time_diff( $from, $to )
?>
<?php echo human_time_diff(get_comment_time('U')).' ago';?>
//2 days ago

9. //wp_list_pluck()
/**
* Pluck a certain field out of each object in a list.
* @return array
*/
function wp_list_pluck( $list, $field );
$foods = array(
! array(
! ! 'name' => 'Banana',
! ! 'color' => 'Yellow',
! ),
! array(
! ! 'name' => 'Apple',
! ! 'color' => 'Red',
! ),
);
$foods_names = wp_list_pluck( $foods, 'name' );
//$foods_names = array( 'Banana','Apple' );
$color_names = wp_list_pluck( $foods, 'color' );
//$color_names = array( 'Yellow','Red' );

10. //wp_localize_script()
//wordcamp.js
jQuery(document).ready(function($){
alert('Welcome to WordCamp Jerusalem 2013');
});
});

11. //wp_localize_script()
/**
* Used to localizes a script.
*
* @return bool Whether the localization was
* added successfully.
*/
function wp_localize_script( $handle, $object_name, $l10n );
?>
<?php
wp_enqueue_script( 'wordcamp-jeruslaem', 'wordcamp.js' );
$translation_array = array(
'welcome' => __( 'Welcome to WordCamp Jerusalem 2013' )
);
wp_localize_script( 'wordcamp-jeruslaem', 'wc_strings',
$translation_array );
?>
<script>
var wc_strings = {
welcome: '2013 ‫,'ברוכים הבאים לוורדקמפ ירושלים‬
};
</script>

12. //wp_localize_script()
// WordCamp.js
jQuery(document).ready(function($){
alert( wc_strings.welcome );
});
});

13. Let’s get to work
cc-by galato901
http://yoav.fr/towork

14. //wp_kses()
/**
* Filters content and keeps only allowable HTML elements.
*
* @return string Filtered content with only
* allowed HTML elements
*/
function wp_kses($string, $allowed_html, $allowed_protocols);
$tags = array(
'em' => array(),
'strong' => array()
);
$html = <<<EOT
<p>
! <b>BOLD</b> is different than <em>italics</em>
</p>
EOT;
echo wp_kses( $html, $tags );
//BOLD is different than <em>italics</em>

15. //wp_mail()
/**
* Send mail, similar to PHP's mail
*
* @return bool Whether the email contents were sent
* successfully.
*/
function wp_mail( $to, $subject, $message, $headers =
'', $attachments = array() );
$to = 'yoav@farhi.org';
$subject = 'I love WordPres';
$message = 'WordPress is The Awesome!!!1';
$mail = wp_mail( $to, $subject, $message );
if( $mail )
! echo 'Mail sent';

16. //wp_remote_get()
/**
* Retrieve the raw response from the HTTP
* request using the GET method.
*
* @return WP_Error|array The response or
* WP_Error on failure.
*/
function wp_remote_get( $url, $args = array() );
$url = 'http://nominatim.openstreetmap.org/search?
q=Netanya&format=json';
$response = wp_remote_get( $url );
if ( ! is_wp_error( $response ) )
! //Do something

17. //wp_trim_words()
/**
* Trims text to a certain number of words.
*
* @return string Trimmed text.
*/
function wp_trim_words( $text, $num_words = 55, $more = null );
$text = "I love WordPress and Joomla";
echo wp_trim_words( $text, 3 );
// I Love WordPress

18. //zeroise()
/**
* Add leading zeros when necessary.
*
* @return string Adds leading zeros to number if needed.
*/
function zeroise($number, $threshold);
$comno = get_comments_number();
// $comno = '2'
$zeroed = zeroise($comno, 2);
// $zeroed = '02'

19. cc by-nc-nd anarosaphotography
http://yoav.fr/happy
Happy

20. questions ?

21. How can I get involved
with the WordPress.org
community?