Question

What would this C# regex look like?

• At least one (1) character in length
• Up to seven (7) characters in length
• Numeric characters

I have this, but I needs to check for 1-7 digits:

var chequeNumRX = new Regex("^[0-9]+$");

Answer 1

In regular expressions, you can use the repetition operator {min,max}.

var chequeNumRX = new Regex(@"^\d{1,7}$");

The above regex would match \d a minimum of 1 time and a maximum of 7 times.

Note that \d is a shorthand character class equivalent to [0-9].