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Re: st: data manipulation prob.
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: data manipulation prob.
Date
Thu, 7 Jun 2012 00:40:16 +0100
On the last question first: the usual Stata way is to add observations
at the end and then -sort-, although you could also -append- to a
one-observation dataset.
If -hits- is always 1, then
sort date
gen obs = _n
su obs, meanonly
di date[ceil(r(mean))] - date[1]
I guess you will now tell us that the real data are more complicated.
Nick
On Wed, Jun 6, 2012 at 10:24 PM, tashi lama <[email protected]> wrote:
> date hits |
> |---------------------------|
> 1. | 10mar2011 01:07:18 1 |
> 2. | 10mar2011 01:09:48 1 |
> 3. | 10mar2011 01:54:00 1 |
> 4. | 10mar2011 02:03:37 1 |
> 5. | 10mar2011 02:11:00 1 |
> |---------------------------|
> 6. | 10mar2011 02:26:00 1 |
> 7. | 10mar2011 02:46:00 1 |
> 8. | 10mar2011 02:47:00 1 |
> 9. | 10mar2011 02:51:09 1 |
> 10. | 10mar2011 02:51:24 1 |
>
> I need to find the time taken to get half of the total hits
>
> summ hits
>
> gen runsum=sum(hits)
>
> date hits x |
> |---------------------------------|
> 1. | 10mar2011 01:07:18 1 1 |
> 2. | 10mar2011 01:09:48 1 2 |
> 3. | 10mar2011 01:54:00 1 3 |
> 4. | 10mar2011 02:03:37 1 4 |
> 5. | 10mar2011 02:11:00 1 5 |
> |---------------------------------|
> 6. | 10mar2011 02:26:00 1 6 |
> 7. | 10mar2011 02:46:00 1 7 |
> 8. | 10mar2011 02:47:00 1 8 |
> 9. | 10mar2011 02:51:09 1 9 |
> 10. | 10mar2011 02:51:24 1 10 |
>
> Now, the prob I am having is I will be comparing r(sum) in var "x" but I need to compute in var "date". So, if r(sum)/2 is 5 then i know to subtract date[5]-date[1]. Any idea?
>
> Also, is it possible to add one date observation on top in date column programmatically. So, I need to add 07mar2011 03:00:00 in date column and because this date comes first than other obs in the dataset, I need to make this as my first obs.
>
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