R中零点之间向量的总和 [英] Sum elements of a vector beween zeros in R

问题描述

我有一个带有零和正数的向量.我只想将 介于 零之间的数字相加.

I have a vector with zeros and positives numbers. I would simply like to sum the numbers that are between the zeros.

一个简单的例子:

x <- c(0,0,0,0,0,1,23,24,54,12,1,23,0,0,0,0,1,23,56,76,0,1,13)

也就是说，我想对元素 1,23,24,54,12,1,23 , 1,23,56,76 和 求和>1,13.

That is, I want to sum the elements 1,23,24,54,12,1,23 , 1,23,56,76 and 1,13.

因此，我想要的输出是:138、156 和 14.

My desired output would therefore be: 138, 156 and 14.

我发现了这个非常相似的问题，但它是在 Python 上的:在 Python 中对零之间的列表元素求和

I found this really similar question but it is on Python: Sum elements of a list between zeros in Python

谢谢.

推荐答案

我们可以使用tapply，用cumsum创建分组，取sum各组.

We can use tapply, creating groups with cumsum and take sum of each group.

new_x <- tapply(x, cumsum(x == 0), sum)
new_x

#  1   2   3   4   5   6   7   8   9  10 
#  0   0   0   0 138   0   0   0 156  14 

由于所有数字都是正数，我们可以忽略 0 并过滤值大于 0 的数字.

Since all numbers are positive we can ignore the ones with 0 and filter the one which has value greater than 0.

new_x[new_x > 0]
#  5   9  10 
#138 156  14 

<小时>

我们也可以使用 sapply 和 split

sapply(split(x, cumsum(x==0)), sum)

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