Search code examples
regexspecial-charactersalphanumeric

Regex - Without Special Characters

I'm using regex to validate username

^[a-zA-Z]+\.[a-zA-Z]{4,10}^'

Unfortunately it doesn't affect if the the value contains special characters such as !@#$%^&*)(':;

I would glad to get some help for Regex that contains:

  • Alphanumeric only (a-zA-Z0-9)
  • Length between 4 - 10 characters.
Solution

  • The conditions you specified do not conform to the regexp you posted.

    the regexp you posted ^[a-zA-Z]+\.[a-zA-Z]{4,10}^ is erroneous I guess, because of the ^ in the end, it will never be matched to any expression, if you want to match with the ^ at the end of the expression, you need to escape it like this \^. but ^ alone means "here is the start of the expression", while $ means "here is the end of the expression".

    Even though, it denotes:

    • It starts with alpha (at least 1).
    • there must be a '.' period character.
    • Now there must be at least 4 alphas.

    The regexp you need is really is:

    ^[a-zA-Z0-9]{4,10}$

    This says:

    • It starts with alphanumeric.
    • There can be a minimum of 4 and a maximum of 10 alphanumeric.
    • End of expression.