创建一个在其他规则增加的行中的每个间隙后增加的索引

问题描述

我有一个 samples 数据框，其中包含一些以规则间隔的时间戳(1 秒间隔)读取的数据.

I've got a samples data frame which contains some readings at regularily-spaced timestamps (1 sec. interval).

                      TS           Pressure     Temperature
[...]
8  2014-08-26 00:18:26.8                105              30
9  2014-08-26 00:18:27.8                108              32
10 2014-08-26 00:18:28.8              109.9              31
11 2014-08-26 00:34:20.8                109              20
12 2014-08-26 00:34:21.8                100              24
13 2014-08-26 00:34:22.8                 95              22
[...]

我只有在某些感兴趣的事件(例如，当 Pressure )期间有记录，并且在这些事件之外没有任何记录.

I only have records during some events of interest (e.g. when Pressure < 110) and don't have any records outside of these events.

我想给每个时期"一个唯一的 ID，其中 Pressure
我制作了另一个数据框 EventBoundaryIndex ，其中包含每个时期的边界索引和相应的 ID 号:

I want to give an unique ID to each "period" where Pressure < 110
I've made another data frame EventBoundaryIndex which holds the boundary indices of each period and the corresponding ID number:

> EventBoundaryIndex
     fromIndex  toIndex  eventID
1            1       10        1
2           11       30        2
[...]

阅读:事件#1 应该跨越samples[0:10, ]，事件#2 跨越samples[11:30, ] 等
现在，我想在原始 samples 数据框中添加一个 eventID 行，以指示每个记录属于哪个 eventID:

read: event #1 should span from samples[0:10, ], event #2 spans samples[11:30, ], etc.
Now I would like to add an eventID row to my original samples data frame to indicate which eventID each record belongs to:

                      TS           Pressure     Temperature   EventID
[...]
8  2014-08-26 00:18:26.8                105              30         1
9  2014-08-26 00:18:27.8                108              32         1
10 2014-08-26 00:18:28.8              109.9              31         1
11 2014-08-26 00:34:20.8                109              20         2
12 2014-08-26 00:34:21.8                100              24         2
13 2014-08-26 00:34:22.8                 95              22         2
[...]

我试过了:

samples$eventID[EventBoundaryIndex$from : EventBoundaryIndex$to] 
        <- EventBoundaryIndex$eventID

但这不起作用.
我想我需要某种形式的 apply 但找不到正确的方法.

but that doesn't work.
I guess I need some form of apply but can't figure out the right way.

或
如果您能想到一种更简单的方法，每次在两个连续时间戳之间检测到超过 1 秒的间隔"时，我的 eventID 索引都会增加，请告诉我！

Or
If you can think of a simpler way to have my eventID index increasing each time a "gap" of more than 1 sec is detected bewteen two consecutive timestamps, let me know!

推荐答案

 samples$eventID <- cumsum(c(TRUE,diff(as.POSIXct(samples$TS))>1))
 samples
 #                      TS Pressure Temperature eventID
 #8  2014-08-26 00:18:26.8    105.0          30       1
 #9  2014-08-26 00:18:27.8    108.0          32       1
 #10 2014-08-26 00:18:28.8    109.9          31       1
 #11 2014-08-26 00:34:20.8    109.0          20       2
 #12 2014-08-26 00:34:21.8    100.0          24       2
 #13 2014-08-26 00:34:22.8     95.0          22       2

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