Regular expression to validate textbox length

Question

I want a regular expression to validate an ASP textbox field with the minimum length of 11 characters and in the middle of the string should be a "-" sign. The sample string is: "0000-011111". I want to validate the textbox to make sure user enters a minimum of 10 numbers with "-" sign after 4 digits using regular expressions. Please help me.
Thank you.

Answer 1

Use

\d{4}-\d{6}

\\d represents a digit, - is a literal dash and the number in the curly brackets force the preceeding token to be present the given number of times.

Answer 2

^\d{4}-\d{6,}$

You should use also ^ at the beginning and $ at the end to ensure that there is nothing before and after your string that you don't want to have. Also important is the {6,} so it will match at least 6 digits, without , it will match exactly 6 digits. If you want set a maximum of digits you can specify after the , , eg {6,20} .