Username :
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^[a-z0-9_-]{3,15}$
Notes :
^ Start of the line
[a-z0-9_-] supported chars and symbols in the list: a-z, 0-9 , underscore ,hyphen
{3,15} Length at least 3 characters and maximum length of 15
$ End of the line.
Password :
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((?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})
Notes :
(?=.*\d) must contains one digit from 0-9
(?=.*[a-z]) must contains one lowercase characters
(?=.*[@#$%]) must contains one special symbols in the list "@#$%"
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