Question

I have a string…

$str = 'bob<br /><br />looked so good<br />tonight!';

I want to replace any instance where there is only one <br /> with two.

At the moment I have…

echo preg_replace('/(<br \/>\s*){1}/', '<br /><br />', $str);

But this put’s two <br /> after bob when it should only go after good.

Any help would be great!

Edit: Output should be…

bob<br /><br />looked so good<br /><br />tonight!

Answer 1

Basically you want a <br /> tag that is not preceded nor followed immediately by another. Thus:

/(?<!<br \/>)<br \/>(?!<br \/>)/

This assumes that all <br /> tags are literally <br /> and not <br>, <br/>, or even <br style="clear:both;">. for better parsing, you should use a DOM parser and look for BR nodes that are not preceded nor followed immediately by another BR node.