为连续序列创建分组变量并分割向量 [英] Create grouping variable for consecutive sequences and split vector

问题描述

我有一个向量，例如 c(1, 3, 4, 5, 9, 10, 17, 29, 30) 我想将相邻"元素组合在一起在不规则的向量中形成一个规则的连续序列，即增加 1，导致:

I have a vector, such as c(1, 3, 4, 5, 9, 10, 17, 29, 30) and I would like to group together the 'neighboring' elements that form a regular, consecutive sequence, i.e. an increase by 1, in a ragged vector resulting in:

L1:1
L2:3,4,5
L3:9,10
L4:17
L5:29,30

L1: 1
L2: 3,4,5
L3: 9,10
L4: 17
L5: 29,30

原始代码(来自前 C 程序员):

Naive code (of an ex-C programmer):

partition.neighbors <- function(v)
{
    result <<- list() #jagged array
    currentList <<- v[1] #current series

    for(i in 2:length(v))
    {
        if(v[i] - v [i-1] == 1)
        {
            currentList <<- c(currentList, v[i])
        }
        else
        {
            result <<- c(result, list(currentList))
            currentList <<- v[i] #next series
        }       
    }

    return(result)  
}

现在我明白了

a) R 不是 C (尽管有大括号)
b) 全局变量是纯粹的邪恶
c) 这是实现结果的一种非常低效的方式

Now I understand that

a) R is not C (despite the curly brackets)
b) global variables are pure evil
c) that is a horribly inefficient way of achieving the result

，所以欢迎任何更好的解决方案.

, so any better solutions are welcome.

推荐答案

大量使用一些 R 习语:

Making heavy use of some R idioms:

> split(v, cumsum(c(1, diff(v) != 1)))
$`1`
[1] 1

$`2`
[1] 3 4 5

$`3`
[1]  9 10

$`4`
[1] 17

$`5`
[1] 29 30

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