R help - May 2013 - Time series analysis

Hi everybody,
I have an analysis problem that seems a little overwhelming to me, but is
probably not too hard to solve for you guys. I have a (fairly large)
dataframe that indicates usage of a resource on different days:

df <-data.frame (
  dstartday =c(rep('2012-02-10', 4), rep('2012-02-11', 5)),
  dstart =c('08:05:00','09:35:00',
'12:00:00','13:00:00', '07:50:00',
'9:45:00', '13:00:00', '14:05:00', '15:50:00'),
  dendday =c (rep('2012-02-10', 3),
'2012-02-11',rep('2012-02-12', 5)),
  dend = c ('08:35:00','09:40:00', '12:20:00',
'01:00:00', '08:35:00',
'11:00:00', '13:15:00', '15:00:00', '17:00:00')
)

Each row reflects an event that starts at the date and time that is
indicated by dstartday/dstart and ends at dendday/dend.
Now I would like to calculate the time intervals in minutes between the
different events that start on a specific day, eg for '2012-02-10' it
should be 60, 140, 40. The interval between the last event of the day and
the first event of the next is not relevant and should be ignored. Events
may run overnight, but there should not be any overlaps between start and
end times.
I have imported all the data as strings.
Any thoughts and suggested readings/packages are really appreciated, thanks!

Best,

Kai

	[[alternative HTML version deleted]]

Hello,

If I understand it well, try the following.


tmp <- lapply(tapply(as.POSIXct(paste(df[,1], df[,2])), df[,1], diff), 
`*`, 60)
lapply(tmp, as.integer)


Hope this helps,

Rui Barradas

Em 09-05-2013 11:45, Kai Mx escreveu:
> Hi everybody,
> I have an analysis problem that seems a little overwhelming to me, but is
> probably not too hard to solve for you guys. I have a (fairly large)
> dataframe that indicates usage of a resource on different days:
>
> df <-data.frame (
>    dstartday =c(rep('2012-02-10', 4), rep('2012-02-11',
5)),
>    dstart =c('08:05:00','09:35:00',
'12:00:00','13:00:00', '07:50:00',
> '9:45:00', '13:00:00', '14:05:00',
'15:50:00'),
>    dendday =c (rep('2012-02-10', 3),
'2012-02-11',rep('2012-02-12', 5)),
>    dend = c ('08:35:00','09:40:00', '12:20:00',
'01:00:00', '08:35:00',
> '11:00:00', '13:15:00', '15:00:00',
'17:00:00')
> )
>
> Each row reflects an event that starts at the date and time that is
> indicated by dstartday/dstart and ends at dendday/dend.
> Now I would like to calculate the time intervals in minutes between the
> different events that start on a specific day, eg for '2012-02-10'
it
> should be 60, 140, 40. The interval between the last event of the day and
> the first event of the next is not relevant and should be ignored. Events
> may run overnight, but there should not be any overlaps between start and
> end times.
> I have imported all the data as strings.
> Any thoughts and suggested readings/packages are really appreciated,
thanks!
>
> Best,
>
> Kai
>
> 	[[alternative HTML version deleted]]
>
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