Hi

I have two columns of data with time in form of HH:MM:SS - representing
start time and end time of an activity. I am trying to calculate the time
difference (duration of the activity).

(1) I first tried
> difftime(btime, etime, units = "mins")
This however gave me the error - Error in
as.POSIXlt.character(as.character(x)) :  character string is not in a
standard unambiguous format

(2) The above error message indicated some problem in format. So I tried
> etime1=as.date(etime, %H:%M:%S")
This gave me the Error: unexpected SPECIAL in "etime1=as.date(etime, %H:%"

I also tried
>etime1=format(etime, %H:%M:%S")
But this gave a similar error - unexpected SPECIAL in "etime1=format(etime,
%H:%"

Any suggestions?

Regards

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