Regex - Without Special Characters

问题:

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.

回答1:

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 minimum of 4 and maximum of 10 of alphanumeric.
• End of expression.

回答2:

Try this:

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