从向量中提取连续序列 | 从向量中提取连续序列

本文介绍了从向量中提取连续序列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有一个名为 v 的向量，其中包含正值和负值以及零.问题是，如何提取(在一个列表中)所有连续的正数序列，即用零分隔的正数序列.

I have a vector called v with positive and negative values as well as zeros. The question is, how to extract (in a list) all the continuous sequences of positive numbers, that is the sequences of positive numbers separated by zeros.

这是 v:

v <- c(-75.09619, -38.31229,   0,  57.17792,  65.55923, 108.52735, 104.29929,  32.47125,0,   0,   0,   0, -26.65008, -49.48638, -79.60670,-90.55343, -34.60761,   0, 21.48842, 38.83820, 42.28727, 0)

输出必须类似于:

[1] 57.17792,  65.55923, 108.52735, 104.29929,  32.47125
[2] 21.48842 , 38.83820, 42.28727

有什么想法吗?

推荐答案

你可以试试:

indices <- which(v[v>=0]==0)
x <- Map(function(x,y) setdiff(v[v>=0][(y+1):(x-1)],0),
         indices[2:length(indices)],
         indices[1:(length(indices)-1)])
x[vapply(x,length,1L)>0]
#[[1]]
#[1]  57.17792  65.55923 108.52735 104.29929  32.47125
#[[2]]
#[1] 21.48842 38.83820 42.28727

我做了什么:

从由 v
使用Map函数，可以提取两个零之间的向量部分
最后一行的目的是从结果中去除没有值的序列(例如，如果原始向量中有两个或多个零的序列)

took the 0 position out of the vector formed with the >=0 values of v
with the Map function, you can extract the part of the vector between two zeros
the last line's purpose is to strip from the result the sequences without values (if for instance there are sequences of two or more zeroes in the original vector)

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