Match x out of y groups in Java regex

Question

Is it possible to write a regex pattern in Java that will match, for example, 2 out of 3 (or 3 out of 4 etc) groups?

For example, I have the following regex:

((?=.*\d)(?=.*[a-z])(?=.*[A-Z]))

which will only allow patterns that match all three groups - i.e. it must contain a number AND a lowercase character AND an uppercase character. I'd like to make it so that it will validate a pattern that contains at least two out of the three groups (e.g. a number and an Uppercase character OR a lower and uppercase characters).

Is it doable in a single statement or am I going to have to write separate regexes and loop through them?

Answer 1

You will need alternations to account for all the possible scenarios:

((?=.*\d)(?=.*[a-z])|(?=.*\d)(?=.*[A-Z])|(?=.*[a-z])(?=.*[A-Z]))

See demo that also matches the whole string with matches():

((?=.*\d)(?=.*[a-z])|^(?=.*\d)(?=.*[A-Z])|^(?=.*[a-z])(?=.*[A-Z])).*