[Tutor] Built In Functions

[Steven D'Aprano]

On Tue, Dec 17, 2013 at 03:21:34PM +0100, Rafael Knuth wrote:

> def PositiveCalculator(a, b):
>     if a > 0 and b > 0:
>         return a + b
>     else:
>         raise ValueError("negative number")
> 
> In this function one negative number is tolerated:
> 
> def PositiveCalculator(a, b):
>     if a > 0 or b > 0:
>         return a + b
>     else:
>         raise ValueError("negative number")
> 
> How would I have to modify these two functions if I wanted to use the
> all( ) or any() function respectively?

I wouldn't do that. The above is perfectly readable and efficient, 
putting them into any/all just makes more work for the reader and for 
the computer.

But if you must, the trick is to remember that a tuple (a, b) is a 
sequence that can be looped over too, so:

    if all(x > 0 for x in (a, b)):

    if any(x > 0 for x in (a, b)):


But as I said, I wouldn't do that for just two variables. Maybe for 
three, or four.

    if a > 0 and b > 0 and c > 0:
    if all(x for x in (a, b, c):



-- 
Steven