Re: Custom function

Hello Mark, Hm... will if ($z) evaluate to true if $z==0? I thought no... Actually, we can use if (isset($z)) -- With best regards from Ukraine, Andre Skype: Francophile My blog: http://oire.org/menelion (mostly in Russian) Twitter: http://twitter.com/m_elensule Facebook: http://facebook.com/menelion ------------ Original message ------------ From: Mark Kelly <php@wastedtimes.net> To: php-general@lists.php.net Date created: , 2:21:36 AM Subject: [PHP] Custom function Hi. On Tuesday 15 Feb 2011 at 23:41 Andre Polykanine wrote: > Give it a default (possible empty) value: > > function MyFunction($x, $y, $z="") { > // function goes here > if (!empty($z)) { > // The optional parameter is given > } > } Using an empty string and the empty() function in this way can lead to subtle and hard to find bugs - for example if $z = 0, the code will not be executed. Note the list of things that are considered empty: http://uk.php.net/manual/en/function.empty.php Instead, consider setting the default value for $z to boolean false: function MyFunction ($x, $y, $z = FALSE) { if ($z) { // do stuff with $z } } In this way almost any value in $z will trigger the conditional code, including 0 or an empty string. The exceptions are FALSE and NULL. If you explicitly need to react to a NULL value, use is_null() to detect it. Cheers, Mark -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php