Alnum: alphanumeric characters.

alnum：字母数字字符。

P {Alnum} — Alphanumeric characters.

p {alnum}—字母数字字符。

SSSSS is the 5-digit alphanumeric sequence number.

SSSSS是5位字母数字的序列号。

The minimum number of alphanumeric characters in a password.

密码中字母数字字符的最小数目。

MMM is the 3-digit alphanumeric model number (0-9, A-Z).

MMM是3位字母数字(0 - 9,a - Z)的型号号码。