conditional expression sought

[Mark McEahern]

Elaine Jackson wrote:

>Sorry to take so long but I wasn't sure what a "unit test" was (the other guy's
>post clarified it). Tell me if this isn't what you're looking for:
>
>falsies=[0,0.0,[],(),{},'',None]
>truies=[49,3.14,[1,2,3],(4,5,6),{7:8,9:10},'nonempty']
>
>def demo(A,B):
>    print "If A is ",A
>    print "and B is ",B
>    print "then (A[0] and B[0]) or (A[1] and B[1]) or (A[2] and B[2]) = ",
>    print (A[0] and B[0]) or (A[1] and B[1]) or (A[2] and B[2])
>
>A=[]
>from random import randint
>for i in range(3):
>    A.append(bool(randint(0,1)))
>B=truies[0:3]
>demo(A,B)
>
>A=[False,False,False]
>B=falsies[0:3]
>demo(A,B)
>print "I would have liked this to be B[2] = ",B[2]
>  
>

Try this:

def whatever(A, B):
    """I don't know what to call this function because it doesn't really 
make sense to me, but, whatever..."""
    c = zip(A, B)
    last = len(c) - 1
    for i, item in enumerate(c):
        a, b = item
        # If both items are true, return b.
        if a and b:
            return b
        # If we're at the last item, return b.
        if i == last:
            return b

print whatever(A, B)

import unittest

class test(unittest.TestCase):

    def testAllFalse(self):
        A = [False, False, False]
        B = [0, 0.0, []]
        expected = []
        actual = whatever(A, B)
        self.assertEquals(actual, expected)

    def testSomeTrue(self):
        A = [0, 1, 0, 1, 0, 1]
        B = ['a', 'b', 'c', 'd', 'e', 'f']
        expected = 'b'
        actual = whatever(A, B)
        self.assertEquals(actual, expected)

unittest.main()