Roman Numerals

bk_roman.py

vals = { "I" : 1, "V" : 5, "X" : 10, "L" : 50, "C" : 100, "D" : 500, "M" : 1000, "_" : 0}
while True:
    input = raw_input("Enter a roman numeral: ").upper()
    if input == "QUIT": break
    input = [ vals[v] for v in input if v in vals ]
    value = 0
    for cur, next in zip(input, (input+[0])[1:]):
        if cur >= next: value += cur
        else:           value -= cur
    print "Value: %d" % value
print "Goodbye."