CODEWITHSUNDEEP
phpregexparsingpreg-match-all
animuson
animuson

Reputation: 54729

How do I process the largest match first in PHP?

Ok, so I tried searching around first but I didn't exactly know how to word this question or a search phrase. Let me explain.

I have data that looks like this:

<!-- data:start -->
    <!-- 0:start -->
        <!-- 0:start -->0,9<!-- 0:stop -->
        <!-- 1:start -->0,0<!-- 1:stop -->
        <!-- 2:start -->9,0<!-- 2:stop -->
        <!-- 3:start -->9,9<!-- 3:stop -->
        <!-- 4:start -->0,9<!-- 4:stop -->
    <!-- 0:stop -->
    <!-- 1:start -->
        <!-- 0:start -->1,5<!-- 0:stop -->
        <!-- 1:start -->1,6<!-- 1:stop -->
        <!-- 2:start -->3,6<!-- 2:stop -->
        <!-- 3:start -->3,8<!-- 3:stop -->
        <!-- 4:start -->4,8<!-- 4:stop -->
    <!-- 1:stop -->
    <!-- 2:start -->
        <!-- 0:start -->0,7<!-- 0:stop -->
        <!-- 1:start -->1,7<!-- 1:stop -->
    <!-- 2:stop -->
<!-- data:stop -->

So it's basically a bunch of points. Here is the code I'm currently using to try and parse it so that it would create an array like so:

Array (
    0 => Array (
        0 => "0,9",
        1 => "0,0",
        2 => "9,0",
        3 => "9,9",
        4 => "0,9"
    ),
    1 => Array (
        0 => "1,5",
        1 => "1,6",
        2 => "3,6",
        3 => "3,8",
        4 => "4,8"
    ),
    2 => Array (
        0 => "0,7",
        1 => "1,7"
    )
)

However, it is returning an array that looks like this:

Array (
    0 => "0,9",
    1 => "0,0",
    2 => "9,0"
)

Viewing the larger array that I have on my screen, you see that it's setting the first instance of that variable when matching. So how do I get it to find the widest match first and then process the insides. Here is the function I am currently using:

function explosion($text) {
    $number = preg_match_all("/(<!-- ([\w]+):start -->)\n?(.*?)\n?(<!-- \\2:stop -->)/s", $text, $matches, PREG_SET_ORDER);
    if ($number == 0) return $text;
    else unset($item);
    foreach ($matches as $item) if (empty($data[$item[2]])) $data[$item[2]] = $this->explosion($item[3]);
    return $data;
}

I'm sure it will be something stupid and simple that I've overlooked, but that just makes it an easy answer for you I suppose.

EDIT: Here is a full output log of the entire data set that I took this sample from. The tags are printed out (replace them with > and <) and it's all inside a giant <code></code> element for easy reading.

Here is the part that's messing up:

Array ( [0] => <!-- 0:start --> <!-- 0:start -->0,9<!-- 0:stop -->  [1] => 0 [2] => <!-- 0:start -->0,9 )

0 => <!-- 0:start -->0,9

So it's stopping at the first occurrence of the stop tag for another piece inside of it. Should I be thinking the opposite direction and processing the smallest pieces first, replacing those so it won't interrupt the larger pieces, and then processing the larger pieces?

Upvotes: 0

Views: 242

Answers (2)

pinaki
pinaki

Reputation: 5473

Well this works for me:

function explosion($text) {
    $number = preg_match_all('/<(.*?)>(.+?)[<]/s', $text, $matches);
    if ($number == 0) return $text;

    $temp = array();
    $data = array();
    foreach($matches[2] as $coords){
        if(trim($coords)==""){
            if(!empty($temp)){
                $data[] = $temp;
                $temp = array();
            }
        }else{
            $temp[] = $coords;
        }
    }
    return $data;
}

The problem with your code was that it was picking up the subtags and the tagged values. Of course it would be hidden when printed in browser, so try taking a log of it for debugging purpose.

Upvotes: 1

sarp
sarp

Reputation: 3750

Here you go:

function explosion($text) {
    preg_match_all("/<!-- ([\d]+):start -->(.+?)<!-- .*:stop -->/", $text, $matches, PREG_SET_ORDER);

    $return = array();
    foreach($matches as $match) {
        if($match[1]==0) {
            $return[] = array();
        }
        $return[count($return)-1][] = $match[2];
    }   
    return $return;
}

Upvotes: 2

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