Is this what you want: TRUE marks the ones to be removed
> mark <- (head(x$timestamp, -1) == tail(x$timestamp, -1)) &
+ (head(x$user_id, -1) == tail(x$user_id, -1))
> x$flag <- c(FALSE, mark)
> x
Source_type timestamp user_id flag
75381 0 07-07-2008-21:03:55 848307909687 FALSE
75379 1 07-07-2008-19:52:55 848307838407 FALSE
75380 2 07-07-2008-19:54:14 848307838407 FALSE
75378 1 07-07-2008-15:24:01 848285633277 FALSE
75374 1 07-07-2008-13:39:17 848273633667 FALSE
75377 2 07-07-2008-13:39:55 848273633667 FALSE
75376 2 07-07-2008-13:39:55 848273633667 TRUE
75375 2 07-07-2008-13:56:05 848273633667 FALSE
75373 1 07-07-2008-17:11:00 848272661427 FALSE
75371 1 07-07-2008-13:19:00 848270431847 FALSE
75372 2 07-07-2008-13:19:14 848270431847 FALSE
75369 1 07-07-2008-12:49:16 848269676907 FALSE
75370 2 07-07-2008-12:49:16 848269676907 TRUE
75366 1 07-07-2008-13:29:15 848263484847 FALSE
75368 2 07-07-2008-13:29:44 848263484847 FALSE
>
On Tue, Sep 23, 2008 at 4:44 PM, Michael Pearmain <[EMAIL PROTECTED]> wrote:
> Hi All,
>
> I'm having trouble selecting rows to delete, that i can't seem to overcome.
>
> Below is some sample data, i am trying to dedup the data based on each user,
> and simultaneously the timestamp (at the side i have highlighted expected
> row to be removed)
>
> I've looked at the lag function but can't seem to make it work?
>
> My logic ran along the lines of an ifelse statement and then remove after
> that, but it doesn't seem to work? Any help appreciated
>
> Let's call the data test
>
> test$lag <- ifelse(test$user_id==lag(test$user_id)
> & test$timestamp==lag(test$timestamp),1,0)
>
> Can anyone help on this?
>
> Mike
>
>
>
> Source_type timestamp user_id
> 75381 0 07-07-2008-21:03:55 848307909687
> 75379 1 07-07-2008-19:52:55 848307838407
> 75380 2 07-07-2008-19:54:14 848307838407
> 75378 1 07-07-2008-15:24:01 848285633277
> 75374 1 07-07-2008-13:39:17 848273633667
> 75377 2 07-07-2008-13:39:55 848273633667
> 75376 2 07-07-2008-13:39:55 848273633667 Remove
> 75375 2 07-07-2008-13:56:05 848273633667
> 75373 1 07-07-2008-17:11:00 848272661427
> 75371 1 07-07-2008-13:19:00 848270431847
> 75372 2 07-07-2008-13:19:14 848270431847
> 75369 1 07-07-2008-12:49:16 848269676907 Remove
> 75370 2 07-07-2008-12:49:16 848269676907
> 75366 1 07-07-2008-13:29:15 848263484847
> 75368 2 07-07-2008-13:29:44 848263484847
>
> Thanks in advance
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
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