Preg_replace not working

You are putting a leading and trailing “/” on your search string, these are part of the syntax for many editor commands, but here PHP just wants the search strings.

Hi. Not according to this example…

<?php
$string = 'April 15, 2003';
$pattern = '/(\w+) (\d+), (\d+)/i';
$replacement = '${1}1,$3';
echo preg_replace($pattern, $replacement, $string);
?>

…found here https://php.net/manual/en/function.preg-replace.php

That example does not work for me ? Only has “/” at start.
Please try it without the “/”.

Here is the code(placed in a shortcode)

function add_user_to_mp3( $content )
{

    return preg_replace('\.mp3(?!\?name)(?!"])',
                            '.mp3?name=[current_user]',
                            $content
                        );

}

add_filter( 'content_save_pre' , 'add_user_to_mp3' , 10, 1);

When I refresh the web page, I get the following error –
Warning: preg_replace(): Delimiter must not be alphanumeric or backslash in

I stuck the same piece of code into one of my web pages and got the correct output-

<?php echo preg_replace('/\.mp3(?!\?name)(?!"])/',
                            '.mp3?name=[current_user]',
                            '[html5_audio src="https://s3.amazonaws.com/sfs-    premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3"]'
                        ); ?>

preg_replace does not seem to work correctly in the context of a shortcode?

But your web page code is not the same as the shortcode handler code. In the webpage version you’ve properly used ‘/’ as regexp delimiters, but not in the shortcode version. preg_replace() works the same in either context as long as your regexp is properly formatted!

BTW, you can use any character as a delimiter as long as it does not occur in the regexp proper. Or if it does it must be escaped.

Thanks for your patience. I changed the shortcode as requested with no change-

function add_user_to_mp3( $content )
{

    return preg_replace('/\.mp3(?!\?name)(?!"])/',
                            '.mp3?name=[current_user]',
                            $content
                        );

}

add_filter( 'content_save_pre' , 'add_user_to_mp3' , 10, 1);

After editing the page containing the shortcode in the wordpress editor, and adding this code  and then saving, the code changes from this:

</div>

[html5_audio src=”https://s3.amazonaws.com/sfs-premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3″%5D

to this:

</div>

[html5_audio src=”https://s3.amazonaws.com/sfs-premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3?name=%5Bcurrent_user%5D”%5D
`
I copied the exact same preg_replace pattern(‘/\.mp3(?!\?name)(?!”])/’) from the shortcode function(which at this point does not seem to work) and pasted it in the web page mentioned previously and did a hard refresh and the pattern behaves as expected ie not doing the replacement(‘.mp3?name=[current_user]’)?

Any ideas I can try. Thanks

sorry. got the tags a little mixed up.

@diondkb,

In addition to @bcworkz answer, PHP uses PCRE functions and it requires you to use delimiters when you’re finding patterns using regex.

Some of the commonly used delimiters are

/foo bar/
#^[^0-9]$#
+php+
%[a-zA-Z0-9_-]%

@diondkb,

Could you tell us in simple terms what your end result should look like? (i.e. Your string and what you want achieve with it?)

Hi,

If the line of text ends in ‘.mp3″]’, then don’t do the replacement. So,

[html5_audio src="https://s3.amazonaws.com/sfs-premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3"]

… would not change, while

<audio src="https://s3.amazonaws.com/sfs-premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3" />

would be changed to look like this

<audio src="https://s3.amazonaws.com/sfs-premium/collection/Rider+Aids/Seat+Aids+and+Feel/Learning+How+to+Stop+Driving+with+Your+Seat/686-Learning-to-Stop-Driving-with-Your-Seat.mp3?name=[current_user]"

Also, if the ‘?name=’ string comes immediately after the ‘.mp3’ not substitution is necessary.

Hope this makes sense.

@diondkb,

Okay, got it.

In my opinion, you should try to write a regular expression to match the part of the string that you’re trying to replace.

Could you see if the following fits your need.

Regex – /(.mp3)[\'|\"][ ]*\/\>/

I have a done a working demo here (https://www.phpliveregex.com/p/gBD). When you visit this page, click on the preg_replace tab.