Python在给定窗口中运行累积总和 [英] Python Running cumulative sum with a given window

问题描述

我想做的是生成一个numpy数组，该数组是给定特定窗口的另一个numpy数组的累积和.

What I want to do is generate a numpy array that is the cumulative sum of another numpy array given a certain window.

例如，给定一个数组[1,2,3,4,5,6,7,8,9,10,11,12]，假设我想要一个窗口为3的累加和.我想要的结果是[1,3,6,9,12,15,18,21,24,27,30,33].我有一个相对较大的numpy数组，并希望使用400的窗口进行累加.

For example, given an array [1,2,3,4,5,6,7,8,9,10,11,12] let's say I want a cumulative sum with a window of 3. What I want as out put would be [1,3,6,9,12,15,18,21,24,27,30,33]. I have a relatively large numpy array and would like to do a cumulative sum with a window of 400.

推荐答案

In [42]: lis=[1,2,3,4,5,6,7,8,9,10,11,12]

In [43]: w=3       #window size

In [44]: [sum(lis[i-(w-1):i+1]) if i>(w-1) else sum(lis[:i+1])  for i in range(len(lis))]
Out[44]: [1, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33]

In [45]: w=4

In [46]: [sum(lis[i-(w-1):i+1]) if i>(w-1) else sum(lis[:i+1])  for i in range(len(lis))]
Out[46]: [1, 3, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42]

对于python 2.4或更低版本，请更改三元运算符:

for python 2.4 or less, change the ternary operator:

(falseValue, trueValue)[condition]而不是trueValue if condition else falseValue

[(sum(lis[:i+1]),sum(lis[i-(w-1):i+1]))[i>(w-1)]  for i in range(len(lis))]

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