我想code了一些简单和Python的识别值的组合，从列表中该款项为定义的值，在一定的耐受性。

I'm trying to code up something simple and pythonic to identify combinations of values from a list which sum to a defined value, within some tolerance.

例如：

如果 A = [0.4,2,3,1.4,2.6,6.3] 和目标值为 5 +/- 0.5 ，那么我想输出（2,3），（1.4,2.6），（2,2.6），（0.4,2,3），（0.4,3,1.4 ）等，如果没有组合找到那么函数应该返回0或无，或类似的东西。

if A=[0.4,2,3,1.4,2.6,6.3] and the target value is 5 +/- 0.5, then the output I want is (2,3), (1.4,2.6), (2,2.6), (0.4,2,3), (0.4,3,1.4) etc. if no combinations are found then the function should return 0 or none or something similar.

任何帮助将是很大的AP preciated。

Any help would be greatly appreciated.

推荐答案

下面是一个递归的方法：

Here's a recursive approach:

# V is the target value, t is the tolerance
# A is the list of values
# B is the subset of A that is still below V-t
def combination_in_range(V, t, A, B=[]):
    for i,a in enumerate(A):
        if a > V+t:    # B+[a] is too large
            continue

        # B+[a] can still be a possible list
        B.append(a)

        if a >= V-t:   # Found a set that works
            print B

        # recursively try with a reduced V
        # and a shortened list A
        combination_in_range(V-a, t, A[i+1:], B)

        B.pop()        # drop [a] from possible list

A=[0.4, 2, 3, 1.4, 2.6, 6.3]
combination_in_range(5, 0.5, A)