我可以在同一行中修剪preg_replace匹配吗？

Question

I am looking into a way to clean a generated class attribute using regular expressions.

Having this html

<div class=" class1 class2 ">

and using this preg

$string = preg_replace('/class=["\'](?P<class>[^"\'<>]+)["\']/i', 'class="$1"', $string);

How do I tell php to trim the trailing spaces around $1? ($1 is basically whats inside class)

Are there other ways to detect and replace end spaces?

Thank you

Edited: basically I am tring to do this

'class="'.trim($1).'"'

but $1 is not available as variable. I already tried $$1 and ${$1}. Maybe there is some other syntax to do this.

Answer 1

You can use slightly modified regex to NOT capture spaces on either side in $1:

$string = preg_replace('/class=["\']\s*(?P<class>[^"\'<>]+?)\s*["\']/i', 'class="$1"', 
          '<div class=" class1 class2 ">') );


var_dump( $string );
string(27) "<div class="class1 class2">"