r - 通过 id R 查找时差

Question

我有以下数据(df)

Id        Timestamp                 Event
 1    2015-11-06 06:11:43           mail subscribed
 1    2015-11-06 06:15:43           Invoice created
 1    2015-11-06 09:15:43           phone call
 2    2015-11-07 08:15:43           New subscription
 2    2015-11-07 08:20:43           Added to customer list.

我正在寻找以下内容，(每个 id 的时差)

例如Id=1有3个不同时间的不同事件，我想根据Id计算事件之间各个时间的差异。

Id        Timestamp                 Event                   Time Difference(Mins)
 1    2015-11-06 06:11:43           mail subscribed           0.0
 1    2015-11-06 06:15:43           Invoice created           5.0         
 1    2015-11-06 09:15:43           phone call                180.0
 2    2015-11-07 08:15:43           New subscription          0.0
 2    2015-11-07 08:20:43           Added to customer list    5.0

我尝试了以下代码，

 diff = function(x) as.numeric(x - lag(x) )
 or diff = function (x) as.numeric(0L,diff(x))
 setDT(df)[, diff2 := diff(timestamp), by = Id]

但是这段代码输出不规则的结果。有什么帮助吗？

Answer 1

试试 ave .不使用任何包。

transform(df, Diff = ave(as.numeric(Timestamp), Id, FUN = function(x) c(0, diff(x))/60))

给予:

  Id           Timestamp                            Event Diff
1  1 2015-11-06 06:11:43                  mail subscribed    0
2  1 2015-11-06 06:15:43                  Invoice created    4
3  1 2015-11-06 09:15:43                       phone call  180
4  2 2015-11-07 08:15:43                 New subscription    0
5  2 2015-11-07 08:20:43           Added to customer list    5

注:这用于输入 data.frame， DF

Lines <- "Id,        Timestamp,                 Event
 1,    2015-11-06 06:11:43,           mail subscribed
 1,    2015-11-06 06:15:43,          Invoice created
 1,    2015-11-06 09:15:43,          phone call
 2,    2015-11-07 08:15:43,          New subscription
 2,    2015-11-07 08:20:43,          Added to customer list"

df <- read.csv(text = Lines)
df$Timestamp <- as.POSIXct(df$Timestamp)

更新 根据评论。