PHP - preg_match解释[关闭]

Question

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. :)

Answer 1

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.