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Re: st: combining consecutive similar observations in time series datasets


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: combining consecutive similar observations in time series datasets
Date   Mon, 18 Mar 2013 18:02:35 +0000

Jeph gave very good advice, but there's a broader problem. In threads starting

http://www.stata.com/statalist/archive/2013-03/msg00424.html

http://www.stata.com/statalist/archive/2013-03/msg00678.html

you previously asked essentially the same kind of question. The
answers included references to programs you can use and articles you
can read.

What is going wrong?

If the answers are too complicated for you, everyone is wasting their
time until you learn the Stata basics to understand what to do and/or
ask questions about what you don't understand. Perhaps you need to
find someone at your university to talk solutions through, as asking
on the list seems not to be helping.

Nick

On Mon, Mar 18, 2013 at 2:09 PM, Jeph Herrin <stata@spandrel.net> wrote:

> You don't indicate if you need to worry about gaps. If not, then this will
> work:
>
>  bys id coded (start) : egen newstart=start[1]
>  bys id coded (end)   : egen newend = end[_N]
>  bys id coded         : keep if _n==1
>
> Or, if you really don't have any other variables
>
>  collapse (min) start (max) end, by(id coded)
>
> will work.
>
>
> On 3/18/2013 2:51 AM, Adeel Yousaf wrote:

>> how can I combine multiple rows of an activity to one row and generate
>> its start and end time, in panel dataset, if the activity occurs
>> adjacently. For example, in the first table 1 the activity code "11"
>> has 3 rows from 4:00 am to 5:30am, I need to get its compact form
>> shown in second table  :-
>>
>> actual dataset:-
>> id      start   end     coded
>> 100003  4:00    4:30    11
>> 100003  4:30    5:00    11
>> 100003  5:00    5:30    11
>> 100003  5:30    5:45    13
>> 100003  5:45    6:00    14
>> 100003  6:00    6:30    14
>> 100003  6:30    7:00    14
>> 100003  7:00    7:15    15
>> 100003  7:15    7:30    16
>> 100003  7:30    8:00    16
>> 100003  8:00    8:15    16
>> 100003  8:15    8:30    17
>> 100003  8:30    8:45    15
>> 100003  8:45    9:00    15
>> 100003  9:00    9:30    15
>> 100003  9:30    10:00   15
>>
>> what i need is:-
>> id      start   end     coded
>> 100003  4:00    5:30    11
>> 100003  5:30    5:45    13
>> 100003  5:45    7:00    14
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