Summierungshäufigkeit basierend auf dem Zeitstempelintervall

Question

Ich habe einen folgenden Datensatz, der die Häufigkeit für bestimmte Zeitstempel angibt.

a <- read.table(header=TRUE, text=" 
Time Freq 
7:00:36 3 
7:00:55 0 
7:02:18 8 
7:02:54 3 
7:04:20 6 
7:04:36 0 
7:05:52 4 
7:06:17 0 
7:07:47 3 
7:08:03 0 
        ") 
a 
     Time Freq 
1 7:00:36 3 
2 7:00:55 0 
3 7:02:18 8 
4 7:02:54 3 
5 7:04:20 6 
6 7:04:36 0 
7 7:05:52 4 
8 7:06:17 0 
9 7:07:47 3 
10 7:08:03 0 

str(a) 
'data.frame': 10 obs. of 2 variables: 
$ Time: Factor w/ 10 levels "7:00:36","7:00:55",..: 1 2 3 4 5 6 7 8 9 10 
$ Freq: int 3 0 8 3 6 0 4 0 3 0 

a$Time <- as.POSIXct(strptime(a$Time, "%H:%M:%OS")) 

str(a) 
'data.frame': 10 obs. of 2 variables: 
$ Time: POSIXct, format: "2016-05-09 07:00:36" "2016-05-09 07:00:55" "2016-05-09 07:02:18" "2016-05-09 07:02:54" ... 
$ Freq: int 3 0 8 3 6 0 4 0 3 0 

Ich möchte wie 2 min die Summe von Frequenzen für feste Zeitintervalle berechnen. Das gewünschte Ergebnis wäre wie folgt aus:

  interval frequency 
1 07:00:01-07:02:00   3 
2 07:02:01-07:04:00  11 
3 07:04:01-07:06:00  10 
4 07:06:01-07:08:00   3 
5 07:08:01-07:10:00   0 

Hier ist mein Versuch:

library(dplyr) 
interval <- 2 

summary <- a %>% 
    mutate(interval = floor((as.numeric(Time - min(Time)))/intrvl)+1) %>% 
    group_by(interval, add = TRUE) %>% 
    summarize(starttime = min(Time), 
      frequency = n()) %>% 
    select(-interval) 
summary 
Source: local data frame [10 x 2] 

      starttime frequency 
       (time)  (int) 
1 2016-05-09 07:00:36   1 
2 2016-05-09 07:00:55   1 
3 2016-05-09 07:02:18   1 
4 2016-05-09 07:02:54   1 
5 2016-05-09 07:04:20   1 
6 2016-05-09 07:04:36   1 
7 2016-05-09 07:05:52   1 
8 2016-05-09 07:06:17   1 
9 2016-05-09 07:07:47   1 
10 2016-05-09 07:08:03   1 

Answer 1

Diese Methode Base R cut und aggregate mit arbeiten:

a$Time <- as.POSIXct(strptime(a$Time, "%H:%M:%OS")) 

# get a factor variable that contains separate levels for every 2 minute interval 
a$interval <- cut(a$Time, breaks="2 min") 
# aggregate the data, summing the frequencies 
aggregate(Freq ~ interval, data=a, FUN=sum)