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External Data Source

Source

Regular Expression
^(?:(?<Visa>4\d{3})|(?<Mastercard>5[1-5]\d{2})|(?<Discover>6011)|(?<DinersClub>(?:3[68]\d{2})|(?:30[0-5]\d))|(?<AmericanExpress>3[47]\d{2}))([ -]?)(?(DinersClub)(?:\d{6}\1\d{4})|(?(AmericanExpress)(?:\d{6}\1\d{5})|(?:\d{4}\1\d{4}\1\d{4})))$