Converting a string into integers

[AuroraBorealis]

I have to write this short program that converts digits/symbols in a string into integers. Basically it takes a string containing none or one operation sign "+" or "-" if __init__ allows it, followed by one or more digits, and can contain blank spaces anywhere. It then returns a triple in this format:

(number of characters in the string including blanks, but not including blanks after the digits, "-1" if there was a "-" right before the digits with no spaces as gap otherwise "1", the integer in the string)

["_" means a blank space]
So "__-" would return (0, 1, 0) since there are no digits
"__+1" would return (4, 1, 1)
"+1" would return (2, 1, 1)
"__-1" would return (4, -1, -1)
"-1" would return (2, -1, -1)
"__+_1" would return (5, 1, 1)
"__-_1" would return (5, 1, 1) since there was a gap between "-" and "1"
"_1-" would return (3, 1, 1) since "-" is in the wrong place
and "_+1___abcde" would return (3, 1, 1) since blank spaces after the digits are ignored and letters are ignored

For the __init__ method, how do create this scanner, and set up whether or not "+" and "-" signs are allowed?
So far I have:

class ConvertToTriple(object):
 
     def __init__(self, take_sign):
          '''Create scanner that converts strings to integers, and accepts leading "+" or "-" signs if take_sign is True.'''
 
     def scan_string(self, s):
          '''Scan a character from string s.'''

How would I set up the __init__ method?
Thanks for any tips.

[Glenton]

Well, I'd start with an algorithm, and then try to code it.

Can you devise an algorithm that would do what you want?