preg_replace - array of individual replacements

Question

I am trying to achieve the following:

$subject = 'a b a';
$search = 'a';
$replace = '1';

Desired result:

Array
(
[0] => 1 b a
[1] => a b 1
)

Is there any way of achieving this with preg_replace?

preg_replace('/\b'.$search.'(?=\s+|$)/u', $replace, array($subject));

will return all the replacments in the same result:

Array
(
[0] => 1 b 1
)

Cheers

Answer 1

I think it is not possible. You can specify a limit of replacements in the optional fourth parameter, but that always starts at the beginning.

It could be possible to achieve what you're looking for with preg_split(). You would just have to split your string on all occasions of your search pattern and then mess with them one by one. If your search pattern is just a simple string, you can achieve the same with explode(). If you need help figuring this approach out, I'll be happy to help.

EDIT: Let's see if this works for you:

$subject = 'a b a';
$pattern = '/a/';
$replace = 1;

// We split the string up on all of its matches and obtain the matches, too
$parts = preg_split($pattern, $subject);
preg_match_all($pattern, $subject, $matches);

$numParts = count($parts);
$results = array();

for ($i = 1; $i < $numParts; $i++)
{
    // We're modifying a copy of the parts every time
    $partsCopy = $parts;

    // First, replace one of the matches
    $partsCopy[$i] = $replace.$partsCopy[$i];

    // Prepend the matching string to those parts that are not supposed to be replaced yet
    foreach ($partsCopy as $index => &$value)
    {
        if ($index != $i && $index != 0)
            $value = $matches[0][$index - 1].$value;
    }

    // Bring it all back together now
    $results[] = implode('', $partsCopy);
}

print_r($results);

Note: This is not tested yet. Please report whether it works.

EDIT 2:

I tested it with your example now, fixed a few things and it works now (at least with that example).

Answer 2

function multipleReplace($search,$subject,$replace) {
    preg_match_all($search, $subject,$matches,PREG_OFFSET_CAPTURE);
    foreach($matches as $match) {
    if (is_array($match)) {
        foreach ($match as $submatch) {
     list($string,$start) = $submatch;
     $length = strlen($string);
     $val = "";
     if ($start - 1 > 0) {
         $val .= substr($subject,0,$start);
     }
     $val .= preg_replace($search,$string,$replace);
     $val .= substr($subject,$start + $length);
     $ret[] = $val;
        }
    }
    }
    return $ret;
}

$search = 'a';

print_r(multipleReplace('/\b'.$search.'(?=\s+|$)/u','a b a','1'));

Output

Array
(
    [0] => 1 b a
    [1] => a b 1
)