我想根据列表中的累积数字来创建新列表。输入是理想的 - 可以分裂为子集,每个子集的总和相等。子集的长度不相等。输入子集数。
每个输出子集代表增量整数[0,1,2,3,...]
,它代替原始输入。整数的数量是子集的数量。
示例:
number of subsets = 2
input = [1, 4, 5]
#cumsum = [1, 5, 10]
subsets = [1,5], [10]
output-subsets = [0,0], [1]
output = [0, 0, 1]
例1:
number of subsets = 4
input = [1, 2, 3, 4, 2, 5, 1, 6]
#cumsum = [1, 3, 6, 10, 12, 17, 18, 24]
subsets = [1,3,6], [10, 12],[17, 18], [24]
output-subsets = [0, 0, 0], [1, 1], [2, 2], [3]
output = [0, 0, 0, 1, 1, 2, 2, 3]
number of subsets = 2
input = [1, 2, 3, 4, 2, 5, 1, 6]
#cumsum = [1, 3, 6, 10, 12, 17, 18, 24]
subsets = [1, 3, 6, 10, 12],[17, 18, 24]
output-subsets = [0, 0, 0, 0, 0], [1, 1, 1]
output = [0, 0, 0, 0, 0, 1, 1, 1]
我尝试修改SO question:
def changelist(lis, t):
total = 0
s = sum(lis)
subset = s/t
for x in lis:
total += x
i= 1
if(total <= subset):
i = 0
yield i
#changelist([input array], number of subset)
print list(changelist([1, 2, 3, 4, 2, 5, 1, 6], 4))
但只有第一个子集是正确的:
output = [0, 0, 0, 1, 1, 1, 1, 1]
我认为numpy.array_split
存在问题strange behaviour of numpy array_split。
我真的很喜欢任何解释或帮助。
答案 0 :(得分:2)
这可以解决您的问题:
def changelist (l, t):
subset = sum(l) / t
current, total = 0, 0
for x in l:
total += x
if total > subset:
current, total = current + 1, x
yield current
示例:
>>> list(changelist([1, 4, 5], 2))
[0, 0, 1]
>>> list(changelist([1, 2, 3, 4, 2, 5, 1, 6], 4))
[0, 0, 0, 1, 1, 2, 2, 3]
>>> list(changelist([1, 2, 3, 4, 2, 5, 1, 6], 2))
[0, 0, 0, 0, 0, 1, 1, 1]
它是如何运作的?
current
存储当前子集的“id”,total
当前子集的总和。x
中的每个元素l
,如果此total
大于每个子集的预期总和,则将其值添加到当前total
(我的代码中为subset
),然后您知道自己位于下一个子集(current = current + 1
)中,并将当前子集的总数“重置”为actuel元素(total = x
) 答案 1 :(得分:1)
您可以在将NumPy
转换为矢量化解决方案的数组后使用input
,假设N
为子集数量,如此处所列 -
def modified_cumsum(input,N):
A = np.asarray(input).cumsum()
return np.append(False,np.in1d(A,(1+np.arange(N))*A[-1]/N))[:-1].cumsum()
样品运行 -
In [31]: N = 2 #number of subsets
...: input = [1, 4, 5]
...:
In [32]: modified_cumsum(input,N)
Out[32]: array([0, 0, 1])
In [33]: N = 4 #number of subsets
...: input = [1, 2, 3, 4, 2, 5, 1, 6]
...:
In [34]: modified_cumsum(input,N)
Out[34]: array([0, 0, 0, 1, 1, 2, 2, 3])
In [35]: N = 2 #number of subsets
...: input = [1, 2, 3, 4, 2, 5, 1, 6]
...:
In [36]: modified_cumsum(input,N)
Out[36]: array([0, 0, 0, 0, 0, 1, 1, 1])