Extract multiple Strings between two String in PHP-CodePudding

I am trying to make this work but I can't:

$str = "<html>1</html><html>2</html><html>3</html>";
$matches = array(); 
preg_match_all("(?<=<html>)(.*?)(?=</html>)", $str, $matches);

foreach ($matches as $d)
{
   echo $d;
}

What I am doing wrong? The output must be:

CodePudding user response：

This should work for you:

$str = "<html>1</html><html>2</html><html>3</html>";
preg_match_all("~(?<=<html>).*?(?=</html>)~", $str, $matches);

foreach ($matches[0] as $d) {
   echo $d;
}

Output:

Changes are:

Use missing regex delimiters ~ in preg_match_all function pattern
Remove capturing group since you are already using lookahead and lookbehind so entire match can be used in further processing
Using $matches[0] in foreach loop instead of $matches
There is no need to declare/initialize $matches before preg_match_all call

CodePudding user response：

You need to add delimiters (I've used !) and you can skip the lookaheads/lookbehinds. Just make a capture group around the numbers you want. Nothing else. Then look in the second matches element for the array with the individual values.

Example:

preg_match_all("!<html>(.*?)</html>!", $str, $matches);

foreach ($matches[1] as $d)
{
   echo $d;
}