[Tutor] Beginner's question

[Oscar Benjamin]

On 22 November 2012 12:55, Peter O'Doherty <mail at peterodoherty.net> wrote:
> Hi list,
> Firstly, apologies for the low-level nature of this question - it's really
> quite basic but I don't seem to be able to solve it.
>
> I need to write a program that examines 3 variables x, y, z, and prints the
> largest odd number. I've tried all sorts of variations and this is the
> current version:
>
> x, y, z = 26, 15, 20
>
> if x > y and x > z and x%2 != 0:
>     print 'x is largest and odd'
> elif y > x and y > z and y%2 != 0:
>     print 'y is largest and odd'
> elif z > x and z > y and z%2 != 0:
>     print 'z is largest and odd'
> else:
>     print 'no odd'
>
>
> A solution should be possible using only the simple operators and keywords
> above, no functions, lists or any other form of iteration. (It's from p. 16
> of Introduction to Computation and Programming Using Python, and no, it's
> not "homework"!)

x, y, z = 13, 14, 15

largest_odd = None
if x % 2:
    largest_odd = x
if y % 2 and y > largest_odd:
    largest_odd = y
if z % 2 and z > largest_odd:
    largest_odd = z

if largest_odd is None:
    print('No odd numbers!')
else:
    print('Largest odd number is %i' % largest_odd)


The code above is just an explicit expansion of what happens if you
solve this problem the normal way (using iteration):

# ValueError when there are no odd numbers
largest_odd = max(v for v in (x, y, z) if v % 2)


Oscar