r - Breaking down a timed sequence into episodes -

i'm trying break down vector of event times episodes. episode must meet 2 criteria. 1) consists of 3 or more events , 2) events have inter-event times of 25 time units or less. data organized in data frame shown below.

so far, figured out can find difference between events diff(eventtime). creating logical vector corresponds events 2nd inter-event criterion, can use rle(episodetimecriterion) total number, , length of episodes.

    eventtime   timedifferencebetweennextevent     episodetimecriterion     25          na                                 na     75          50                                 true     100         25                                 true     101         1                                  true     105         4                                  true     157         52                                 false     158         1                                  true     160         2                                  true     167         7                                  true     169         2                                  true     170         1                                  true     175         5                                  true     178         3                                  true     278         100                                false     302         24                                 true     308         6                                  true     320         12                                 true     322         459                                false 

however, know timing of episodes , 'rle()' doesn’t let me that.

ideally generate data frame looks this:

    episode      eventsperepisode   episodestarttime   episodeendtime     1            4                  75                 105     2            7                  158                178     3            3                  302                322 

i know simple problem being new r, solution can envision series of loops. there way of doing without loops? or there package lends sort of analysis?

thanks!

edited clarity. added desired outcome data fame , expanded example data make clearer.

you've got pieces need. need make variable gives each episode number/name can group it. rle(...)$length gives run lengths, use rep repeat number number of times:

runs <- rle(df$episodetimecriterion)$lengths   # don't need variable, makes code more readable df$episode <- rep(1:length(runs), runs) 

so df looks like

> head(df)   eventtime timedifferencebetweennextevent episodetimecriterion episode 1        25                             na                   na       1 2        75                             50                 true       2 3       100                             25                 true       2 4       101                              1                 true       2 5       105                              4                 true       2 6       157                             52                false       3 

now use dplyr summarize data:

library(dplyr) df2 <- df %>% filter(episodetimecriterion) %>% group_by(episode) %>%    summarise(eventsperepisode = n(),              episodestarttime = min(eventtime),              episodeendtime = max(eventtime)) 

which returns

> df2 source: local data frame [3 x 4]    episode eventsperepisode episodestarttime episodeendtime     (int)            (int)            (dbl)          (dbl) 1       2                4               75            105 2       4                7              158            178 3       6                3              302            320 

if want episode numbers integers starting one, can clean with

df2$episode <- 1:nrow(df2) 

data

if wants play data, results of dput(df) before running above code:

df <- structure(list(eventtime = c(25, 75, 100, 101, 105, 157, 158,      160, 167, 169, 170, 175, 178, 278, 302, 308, 320, 322), timedifferencebetweennextevent = c(na,      50, 25, 1, 4, 52, 1, 2, 7, 2, 1, 5, 3, 100, 24, 6, 12, 459),      episodetimecriterion = c(na, true, true, true, true, false,      true, true, true, true, true, true, true, false, true, true,      true, false)), .names = c("eventtime", "timedifferencebetweennextevent",      "episodetimecriterion"), row.names = c(na, -18l), class = "data.frame")