Calculate Avg Time in R

Question

My Dataframe called copy1:

    copy1
Source: local data frame [4 x 4]
Groups: GM [2]

      GM Avg.Start.Time Avg.Close.Time Avg.Last.Task.Duration
  (fctr)         (fctr)         (fctr)                  (int)
1   ED          13:15          16:16                    181
2   ED          16:12          17:44                     92
3   LD          15:32          17:27                    115
4   LD          14:38          17:11                    153

I want to calculate Avg.Close.Time Per GM

I have tried:

copy1$Avg.Start.Time <-strptime(copy1$Avg.Start.Time, "%H:%M")
copy1%>%group_by(GM)%>%
        summarise(mean(copy1$Avg.Start.Time,na.rm=T))

But get this:

Error: column 'Avg.Start.Time' has unsupported type : POSIXlt, POSIXt

I have also tried using lubridate:

copy1$Avg.Start.Time <- hm(copy1$Avg.Start.Time)

mean(copy1$Avg.Start.Time,na.rm = T)

But get "0"

Any ideas how can I calculate Avg.Start.Time Per GM?

Answer 1

You can use as.POSIXct to do the conversion, the result of which can be used for mean:

result <- copy1%>%group_by(GM)%>%
  summarise(mean(as.POSIXct(Avg.Start.Time, format="%M:%S"),na.rm=T))

However, this will add the current date to the time:

print(result)
## A tibble: 2 x 2
##      GM mean(as.POSIXct(copy1$Avg.Start.Time,...
##  <fctr>                                   <time>
##1     ED                      2016-08-24 00:14:54
##2     LD                      2016-08-24 00:15:05

---

As pointed out by the OP, we can format the result to remove the date:

result <- copy1%>%group_by(GM)%>%
  summarise(Avg.Start.Time=format(mean(as.POSIXct(Avg.Start.Time, format="%M:%S"),na.rm=T), format="%M:%S"))
## A tibble: 2 x 2
##      GM Avg.Start.Time
##  <fctr>          <chr>
##1     ED          14:43
##2     LD          15:05