On 08/03/07, Alan Gilfoy <[EMAIL PROTECTED]> wrote:
This, I heard, is more difficult than digital-to-Roman, since you have to "read" the subtractive cases, with a smaller numeral placed before a larger numeral, without simply adding all the numerals' values up I'm going to use a raw_input prompt to ask the user which Roman numeral he/she wants to convert. How do I "screen" for inputs that have characters besides "I", "V", "X", "L", "C", "D", or "M"? Second Python question: I know there's a way to "find out" the name of the first item in a list (ListName[0]), but is there a way to find out the first character of a string? Also, is there a way to "ask" Python what characters are before and after the character in the string that you're asking about? For example, usign the sample string "MCMXVII" (1917): How would you ask Python: "What's the 3rd character in this string?" (returns "M") "What's before that character?" (returns "C") Pseudocode time: If character Y is "M": and the character before character Y is "C", add 900 to digital_result and remove that "C" and that "M" from the string. #How would you do *that*? and the character before character Y is another "M", or if character Y is the first character in the string, add 1000 to digital_result and remove that "M" from the string.
you can index a string just like a list:
roman_numeral = "MCMXVII" roman_numeral[2]
'M'
roman_numeral[2-1]
'C' HTH Adam
_______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
