python - 求和两个维度的最简单方法？ (Python)

Question

我需要求和两个维度的帮助。

假设我有 [[0,1,2],[3,4,5]] 作为我的维度，将这些数字相加将返回 int 15。

   def sum_dimensions(x):
       x = []
       answer = sum(x)
       return int(x)

感谢指出我在代码中的错误。

Answer 1

让我们深入了解一下。我在我的机器上使用了以下数据集:

data = list(list(range(100000)) for i in range(1000))

我有以下结果:

In [13]: %%timeit                                             
sum(sum(ele) for ele in data)
   ....: 
1 loops, best of 3: 1.15 s per loop

In [14]: %%timeit                                             
sum([sum([item for item in ele]) for ele in data])
   ....: 
1 loops, best of 3: 3.78 s per loop


In [15]: %%timeit                                             
sum(j for i in data for j in i)
   ....: 
1 loops, best of 3: 4.92 s per loop

In [16]: %%timeit                                             
sum(itertools.chain.from_iterable(data))
   ....: 
1 loops, best of 3: 1.61 s per loop

In [18]: %%timeit
sum(map(sum, data))
   ....: 
1 loops, best of 3: 1.16 s per loop

但是对于小数据集，itertools 变体比 sum(sum 变体快 2 倍。sum(map(sum 似乎精确映射到 sum(sum(ele) for ele in data) 结构