thank you so much for your help!
sara
--- Michael Blasnik <[email protected]> ha
scritto:
> Here's one way to only drop matched pos/neg pairs:
>
> gen abscharge=abs(charge)
> bysort personid proc date abscharge (charge) : gen
> byte
> todrop=charge!=charge[_n-1] & _n>1
> bysort personid proc date abscharge (charge) :
> replace todrop=1 if
> charge!=charge[_n+1] & _n<_N
> drop if todrop==1
> drop todrop
>
> You would need to run this more than once if there
> are multiple matched
> pos/beg pairs with the same values. The hasnegative
> var is superfluous for
> this approach since the only way that
> charge!=charge[_n-1] within the same
> abscharge is if they differ in sign.
>
> Michael Blasnik
>
>
> ----- Original Message -----
> From: "sara borelli" <[email protected]>
> To: <[email protected]>
> Sent: Wednesday, March 07, 2007 12:37 PM
> Subject: Re: st: Re: eliminate negative values and
> their positive
> counterpart
>
>
> > Hi Michael,
> >
> > I am sorry to write again about the question of
> > yesterday
> > I am not sure how I would change the code you
> > suggested in the following case:
> >
> > claimnum personid servdate charge proc
> > 4087 1000124 2001-06-06 +25274.25 121
> > 4510 1000124 2001-06-06 -25274.25 121
> > 4511 1000124 2001-06-06 +25274.25 121
> >
> > If I want to eliminate the negative charge AND
> both
> > positive counterparts I just type drop if
> > hasnegative==1.
> >
> > The problem is that I might need to drop the
> negative
> > and only one of the positive counterparts, but the
> > only variable that can distinguish between the two
> > positives is claimnum, which cannot be used to
> define
> > a group since it is unique to each observation
> >
> > thank you in advance
> > Sara
>
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