Regex to match number with different digits and minimum length

Question

I am trying to write a regex (to validate a property on a c# .NET Core model, which generates javascript expression) to match all numbers composed by at least two different digits and a minimum length of 6 digits.

For example:

222222 - not valid

122222 - valid

1111125 - valid

I was trying the following expression: (\d)+((?!\1)(\d)) , which matches the sequence if has different digits but how can I constrain the size of the whole pattern to {6,} ?

Many thanks

Answer 1

You may use

^(?=\d{6})(\d)\1*(?!\1)\d+$

See the regex demo

Details

• ^ - start of string
• (?=\d{6}) - at least 6 digits
• (\d) - any digit is captured into Group 1
• \1* - zero or more occurrences of the value captured in Group 1
• (?!\1) - the next digit cannot be the same as in Group 1
• \d+ - 1+digits
• $ - end of string.