Auto Linking Words But Only One Time

Question

I highly need a piece of code which will replace a simple word with a hypertext link, using str_replace method. And fortunately I found this code below, but the problem is that it repeats the link with all matching keywords, whereas I want to add the link only once and forget other matching keywords.

For example, if it sees "nursery rhymes", replace it with a hypertext link, but do not add the link again with "nursery rhymes", "rhymes" or "poems" keywords on same page. One URL only one time.

I also heard that it's probably not possible with str_replace, but possible with preg_replace, which could limit the occurrence of replacements.

Please help. I am not very familiar with PHP or coding, so please use complete code, so I can simply copy and paste in my functions.php. Here is the code I am using:

function wp_affiliate_links($text) {
    $replace = array(
        ' nursery rhymes ' => ' <a href="http://www.nurseryrhymes.me/">nursery rhymes</a> ',
        ' poems ' => ' <a href="http://www.nurseryrhymes.me/">poems</a> ',
        ' rhymes ' => ' <a href="http://www.nurseryrhymes.me/">rhymes</a> ',
    );
    $text = str_replace(array_keys($replace), $replace, $text);
    return $text;
}
add_filter('the_content', 'wp_affiliate_links');
add_filter('the_excerpt', 'wp_affiliate_links');

Answer 1

Can't you pass limit number of replacements in str_replace? Like that

$text = str_replace(array_keys($replace), $replace, $text, 1);

EDIT:

Sorry I was thinking about something else and missed this one. You can use preg_replace and set limit in it. Like this one.

function wp_affiliate_links($text){
    $replace = array(
        '/ nursery rhymes /' => ' <a href="http://www.nurseryrhymes.me/">nursery rhymes</a> ',
        '/ poems /' => ' <a href="http://www.nurseryrhymes.me/">poems</a> ',
        '/ rhymes /' => ' <a href="http://www.nurseryrhymes.me/">rhymes</a> ',
    );
    $text = preg_replace( array_keys($replace), $replace, $text, 1 );
    return $text;
}
add_filter('the_content', 'wp_affiliate_links');
add_filter('the_excerpt', 'wp_affiliate_links');

EDIT 2:

Try this one.

function wp_affiliate_links($text){
    $replace = array(
        '/ nursery rhymes /' => ' <a href="http://www.nurseryrhymes.me/">nursery rhymes</a> ',
        '/ poems /' => ' <a href="http://www.nurseryrhymes.me/">poems</a> ',
        '/ rhymes /' => ' <a href="http://www.nurseryrhymes.me/">rhymes</a> ',
    );
    foreach ( $replace as $key ) {
        $text = preg_replace( array_keys($replace), $replace, $text, 1 );
        return $text;
    }
}
add_filter('the_content', 'wp_affiliate_links');
add_filter('the_excerpt', 'wp_affiliate_links');