文數字

Also known as alphameric, alphanumerical, alphanumeric character

thumb|A black-headed gull ringed with an alphanumeric plastic ring that makes it easier to read from a distance. Alphanumeric characters or alphanumerics are characters belonging to the English alphabet or Arabic numerals. It includes both lower and uppercase characters. The complete list of alphanumeric characters in lexicographically ascending order is: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.