Question

I am having a hard time getting my head around this regex. What I am trying to do is as follows:

• Match any occurrence of words that begin with #. So, for example, if the code finds the following tags #jon, #james, #jill, then it should hide the text.
• But if the code finds occurrences of the following tag: #ADMINISTRATOR, then it should display the text
• In addition, if the code finds no occurrences of any words tagged with #, it should also display the text.

Essentially, I want to hide any comments that are hashed tagged with a user name other than ADMINISTRATOR.

So far, I have the following code:

if (mb_ereg_match(".*(#[^ADMINISTRATOR]){1,}.*", $comment))
{
    $hideComment = true;
}else
{
    $hideComment = false;
}

The above code works for the most part, except for when the text being searched contains any one of the following:

#A, #AD, #ADM, #ADMI, #ADMIN, etc.

then the code does not hide the comment, which is not what I want. I only want an exact match to ‘#ADMINISTRATOR’ to display the comments. Plus, any comment that contains no tags should also be displayed.

Any idea what I am doing wrong?

Answer 1

This is a negative lookahead based regex that will work for you:

(?i)#(?!ADMINISTRATOR)\w+

Here is a Live Demo