如何从一组元组中找到一个值最接近给定元组的元组？

Question

I'm working with python and have a dict where the keys are tuples with 3 values each.

I'm computing another tuple with 3 values, and I want to find the tuple in the keys of the dict with the closest values to this newly computed tuple.

How should I go about doing this?

Answer 1

You could do something like this:

def euclid2(x,y):
    return sum((xi-yi)**2 for xi,yi in zip(x,y))

def closestTuple(target,tuples, dist = euclid2):
    return min((dist(t,target),t) for t in tuples)[1]

#test:
target = (3,5,1)
tuples = [(3,1,2), (4,1,5), (6,1,7), (4,4,2), (1,5,7)]
print(closestTuple(target,tuples)) #prints (4,4,2)

This finds the tuple which is closest to the target tuple in the Euclidean metric. You could of course pass another function for the dist parameter.

Answer 2

You are probably looking for the abs() of the difference, eg:

>>> from random import randint
>>> d = [tuple(randint(1, 20) for _ in range(3)) for _ in range(5)]
>>> d
[(4, 13, 10), (12, 18, 19), (11, 18, 8), (16, 17, 4), (2, 4, 10)]
>>> k = tuple(randint(1, 20) for _ in range(3))
>>> k
(14, 13, 1)
>>> min(d, key=lambda x: sum(abs(m-n) for m, n in zip(k, x)))
(16, 17, 4)

Answer 3

You could try the following (i used a list), and simply iterate over each element, and take the difference between each element in the tuple, then in the end sort the sums of the differences and look for the smallest amount

a = [(1, 2, 3), (3, 4, 5), (5, 6, 7)]
b = (2, 4, 5)
c = []
for x in a:
     c[a.index(x)] = 0
     for i in range(len(x)):
            c[i]+=x[i]-b[i]