Ada,
David's solution would flag the first obersvation in the pair exact
opposites, but a slight change will make it flag the second observation of
the pair.
mark weird if o[_n-1] == f[_n] & f[_n-1] == o[_n]
Example:
. l, clean
o f
1. 1 23
2. 14 235
3. 35 90
4. 45 87
5. 87 45
. mark weird if o[_n-1] == f[_n] & f[_n-1] == o[_n]
. l, clean
o f weird
1. 1 23 0
2. 14 235 0
3. 35 90 0
4. 45 87 0
5. 87 45 1
And then:
drop if weird == 1
Scott
----- Original Message -----
From: "Ada Ma" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 26, 2003 8:49 PM
Subject: st: Re: how to flag up obs that are the reverse of other obs?
> Hi again,
>
> My original post:
> I want to know how to drop some observations. For example I have the
> following data, the numbers are identifiers:
>
> Original Fake
> 1 23
> 14 235
> 35 90
> 45 87
> 87 45
>
> Now the 4th and 5th pairs are the exact opposite of one another. I want
to
> drop the 5th observation, but I don't know I can use the data to flag up
> such observations so that I can drop it. Could someone show me the light?
>
> My thanks to David Airey's suggestion, but it didn't work. I tried
> something in the vein of what he's suggested, e.g.:
>
> local i=1
> local j=1
> gen weirdob=.
>
> while `i'<82845 {
>
> while `j'<`i' {
> replace weirdob[`i']=1 if original[`i']==fake[`j'] &
> fake[`i']==original[`j']
> local j=`j'+1
> }
>
> local i=`i'+1
> }
>
> Stata wouldn't do weights. Are there other strategies that I can employ??
>
> Thanks again.
>
> Ada Ma
> Department of Economics
> University of Aberdeen, Scotland
> [email protected]
> *
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*
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