Given a string text, return [letters, digits, spaces, others]: how many characters are English letters, how many are digits, how many are spaces, and how many are anything else. Behind the scenes every character is a number — its character codeCharacter Code (ASCII)The number a character is stored as, e.g. 'A' = 65, 'a' = 97, '0' = 48.. Letters and digits occupy consecutive ranges of codes, which is what makes simple range checks work. Built-in tests like isalpha wrap those checks in readable names.