Core Python Programming (2nd Edition)

17 other.__num, \
18 self.__string + other.__string)
19 else:
20 raise TypeError, \
21 'Illegal argument type for built-in operation'
22
23 def __mul__(self, num): # define for o*n
24 if isinstance(num, int):
25 return self.__class__(self.__num * num
26 self.__string * num)
27 else:
28 raise TypeError, \
29 'Illegal argument type for built-in operation'
30
31 def __nonzero__(self): # False if both are
32 return self.__num or len(self.__string)
33
34 def __norm_cval(self, cmpres):# normalize cmp()
35 return cmp(cmpres, 0)
36
37 def __cmp__(self, other): # define for cmp()
38 return self.__norm_cval(
39 cmp(self.__num, other.__num)) + \
40 self.__norm_cval(
41 cmp(self.__string, other.__string))
Given the above criteria, we present the code below for numStr.py, with some sample execution:
>>> a = NumStr(3, 'foo')
>>> b = NumStr(3, 'goo')
>>> c = NumStr(2, 'foo')
>>> d = NumStr()
>>> e = NumStr(string='boo')
>>> f = NumStr(1)
>>> a
[3 :: 'foo']
>>> b
[3 :: 'goo']
>>> c
[2 :: 'foo']
>>> d
[0 :: '']
>>> e
[0 :: 'boo']
>>> f
[1 :: '']
>>> a < b
True
>>> b < c
False
>>> a == a
True
>>> b * 2
[6 :: 'googoo']
>>> a * 3