Im a beginner in PHP I just want to ask can someone explain to me this line of code.
(preg_match('/^\w{5,}$/', $username))
Thankyou in advance. :) Your answer is so much appreciated. :)
Your PHP match string is
/^\w{5,}$/
and a PHP match string is surrounded by / characters which are not part of the RegEx string itself.
According to the comments your problem is about understanding regular expressions, not PHP.
^ is the beginning of the line, correct
$ is the end of the line, correct
\w Any word character (letter, number, underscore)
a{5,} does mean 5 or more characters 'a'
Therefore: If there are 5 or more any word characters in the username the function returns a positive result.
Or even easier: A username needs to contain at least five any word characters.
Learn more about regular expressions and how they work. Some explanation can be found in this comment.