Coolest Python recipe of all time

[Raymond Hettinger]

[Steven D'Aprano]:
> As written, amb is just a brute-force solver using more magic than is
> good for any code, but it's fun to play with.

With a small change in API, much of the magic isn't needed.

from itertools import product

def amb(func, *argument_ranges):
    for args in product(*argument_ranges):
        if func(*args):
            print(args)

amb(lambda a,b,c,d: 5*a+10*b+20*c+50*d == 45,
    range(3, 21),   # number of 5 cent coins
    range(11),      # number of 10 cent coins
    range(6),       # number of 20 cent coins
    range(3),       # number of 50 cent coins
)

def test(a, b, c, d):
    s = "The %s brown %s jumped over the %s %s." % (a, b, c, d)
    num_vowels = sum(s.count(c) for c in 'aeiou')
    return num_vowels in (12, 18, 19)

amb(test,
    ['quick', 'slow', 'hungry', 'wise-old'],
    ['fox', 'hare', 'turtle', 'kangaroo'],
    ['lazy', 'stupid', 'sleepy', 'confused'],
    ['dog', 'aardvark', 'sloth', 'wombat'],
)

amb(lambda x, y, z: x*x + y*y == z*z,
    range(1, 11),
    range(1, 11),
    range(1, 11),
)


Raymond

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