How to write a regular expression to validate characters in username and password?

Question

Regular Expressions

Expressions are needed for:
1) Username field: only latin letters are needed, case does not matter
2) Password field, where needed: - at least 6 letters, at least one small letter, at least one capital letter, at least one number, and no special characters like [email protected]#$%^&*()+;
Help, good people!

Answer 1

/[a-z]+/i

/(?=^[a-zA-Z\d]{6,}$)(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).*/