Question

$string = 'test check one two test3';
$result = mb_eregi_replace ( 'test|test2|test3' , '<$1>' ,$string ,'i');
echo $result; 

This should deliver: <test> check one two <test3>

Is it possible to get, that test and test3 was found, without using another match function ?

Answer 1

You can use preg_replace_callback instead:

$string = 'test check one two test3';
$matches = array();
$result = preg_replace_callback('/test|test2|test3/i' , function($match) use ($matches) {
    $matches[] = $match;
    return '<'.$match[0].'>';
}, $string);
echo $result;

Here preg_replace_callback will call the passed callback function for each match of the pattern (note that its syntax differs from POSIX). In this case the callback function is an anonymous function that adds the match to the $matches array and returns the substitution string that the matches are to be replaced by.

Another approach would be to use preg_split to split the string at the matched delimiters while also capturing the delimiters:

$parts = preg_split('/test|test2|test3/i', $string, null, PREG_SPLIT_DELIM_CAPTURE);

The result is an array of alternating non-matching and matching parts.