something wrong with preg_replace?

Question

After managing to use preg_match_all, I would then want to replace the matched texts with matchedText, however it seems not working. Take a look at my code, what have I done wrong?

    <?php
    $tweets = getTweets($profile->twitter_id);

    for($i=0;$i<4;$i++):
        // finds matches
        $num_matches = preg_match_all('/@\w+/', $tweets[$i]->description, $matches);

        if($num_matches):
            echo $num_matches.'<br />';
            for($c=0;$c<$num_matches;$c++):

                $subject = $tweets[$i]->description;
                $pattern = array();
                $pattern[$c] = $matches[0][$c];
                $replacement = array();
                $replacement[$c] = '<a href="https://twitter.com/#!/">'.$matches[0][$c].'</a>';

            endfor;
                echo preg_replace($pattern, $replacement, $subject).'<br /><br />';

        else:
            echo auto_link($tweets[$i]->description).'<br /><br />';
        endif;
    endfor;
?>

Answer 1

You need to define $pattern and $replacement outside of the loop, otherwise they will get reinitialized to an empty array on each iteration:

$pattern = array(); $replacement = array();
for($c=0;$c<$num_matches;$c++):

Answer 2

Maybe, your preg_replace -ing without using a pattern: $matches[0][$c] holds a string, not a pattern with delimiters. Then again, I might be wrong. It could be helpful to see what your matching, and what you're replaceing

Nips , I can't believe I overlooked the array declaration inside the loop, too... of course, that's the first thing you should fix!

Answer 3

Thank you for the answers guys, however I stopped using preg_replace, I used str_replace instead. It works fine. Here's my final code.

    <?php
        $tweets = getTweets($profile->twitter_id);

        for($i=0;$i<4;$i++):
            // first, explode the description to eliminate the username in the description
            $tweet_des = $tweets[$i]->description;
            $tweet_no_username_des = explode(':',$tweet_des,2); // added a limit parameter, ensuring only the username will be excluded
            $new_tweet_description = $tweet_no_username_des[1].'<br />';

            // the date the tweet is published
            echo $date_pub = $tweets[$i]->pubDate;

            // using preg_match_all to find matches, texts having '@' as the first letter
            $num_matches = preg_match_all('/@\w+/', $tweets[$i]->description, $matches);
            if($num_matches):   // if match(es) are found
                $search_arr = array();  // declared an array to contain the search parameter for str_replace
                $replace_arr = array(); // declared an array to contain the replace parameter for str_replace
                for($c=0;$c<$num_matches;$c++):
                    $search_arr[$c] = $matches[0][$c];
                    $name_links[$c] = explode('@',$search_arr[$c]);
                    $not_link_name = $name_links[$c][1];
                    $replace_arr[$c] = '<a href="http://twitter.com/#!/'.$not_link_name.'" target="_blank">'.$matches[0][$c].'</a>';
                endfor;
                echo auto_link(str_replace($search_arr, $replace_arr, $new_tweet_description)).'<br />';
            else:
                echo auto_link($new_tweet_description).'<br />';
            endif;
        endfor;
    ?>

Initially my problem was to find the texts starting with '@', and would link it to the respective accounts in Twitter. Please feel free to criticize my code, I think it's still buggy though. :)