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Re: st: Subtract Closest Cell Which has A Value
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: Subtract Closest Cell Which has A Value
Date
Fri, 26 Oct 2012 20:06:33 +0100
All that said, the first step here is an interpolation that treats
each series as a step function. Have you considered other
interpolation methods, including
linear (official -ipolate-)
cubic (SSC -cipolate)
cubic spline (SSC -csipolate-)
?
Nick
On Fri, Oct 26, 2012 at 9:49 AM, Nick Cox <[email protected]> wrote:
> This can be solved using the same techniques as for your previous problem.
>
> See my previous posting.
>
> You need a variable that is the previously observed value and one that
> is the next observed value. You get those variables by copying down in
> a cascade in the usual (panel id, time) order and then again after
> reversing time.
>
> Then you use the previous value if the timeline date is positive and
> the next value if it is negative.
>
> See also
>
> FAQ . . . . . . . . . . . . . . . . . . . . . . . Replacing missing values
> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
> 2/03 How can I replace missing values with previous or
> following nonmissing values?
> http://www.stata.com/support/faqs/data/missing.html
>
> (Reversing time is one of the top tricks many people need occasionally
> in Stata but often don't seem to know about.)
>
> NIck
>
> On Fri, Oct 26, 2012 at 3:41 AM, Lisa Wang <[email protected]> wrote:
>> Dear all,
>>
>> I have another question. I have two columns of values - variables A
>> and B to make it simple. I would like to A-B in a new column C;
>> however, column B has a lot of missing values (.), so it doesn't seem
>> that simple. Variable A is complete, so no missing data. I would like
>> Stata to find the nearest cell (data is already sorted by column D)
>> with a value in column B to subtract off for each panel that I have.
>>
>> For instance,
>>
>> 51 . 31
>> 50 . 30
>> 47 20 27
>> 51 . 31
>> 25 . 5
>> 49 . 29
>> 45 . 25
>> 24 . 4
>> 51 . 1
>> 22 . -28
>> 27 . -23
>> 57 . 7
>> 20 . -30
>> 57 50 7
>> 59 . 9
>> 33 . -17
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