Handy unknown feature in PHP function explode()

Posted by Lee under Programming

I accidentally came across a mighty handy feature in the PHP explode() function today whilst doing an update to Breeze CMS that I cannot see documented anywhere. It certainly saved me what would have been a full re-write or reconsideration of the function I was writing!

What I found was that when using it in the following example:

$content = "Blah blah ##bitname## some more blah and then ##bitname## a bit more";
$parts = explode('##', $content);
print_r($parts);

The results were

Array
(
[0] => Blah blah
[1] => bitname
[2] =>  some more blah and then
[3] => bitname
[4] =>  a bit more
)

Which is exactly what I expected, but when you have the deliminator (##) at the start of the string like below

$content = "##bitname## blah blah ##bitname## some more";

You get the following result:

Array
(
[0] =>
[1] => bitname
[2] =>  blah blah
[3] => bitname
[4] =>  some more
)

Whats so special? See the first empty value in the array? The explode function creates an empty first array value if the first characters are the deliminator you are using. I don’t know if this is an intended feature but it is perfect for us as we know that each ‘bit name’ is always going to be an odd number.