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Re: st: Drop Observations Satisfying List
From
Phil Schumm <[email protected]>
To
<[email protected]>
Subject
Re: st: Drop Observations Satisfying List
Date
Tue, 10 Sep 2013 20:26:42 -0500
On Sep 10, 2013, at 7:54 PM, Lisa Wang <[email protected]> wrote:
> I have a column of dates in one dataset ("A") and my actual analysis in another dataset ("B"). I would like to drop all the observations in "B" which has a date found in dataset "A".
>
> There are about 750 or so dates in dataset "A".
>
> I am unsure how to do a drop if/ keep if when the condition could be a whole array of dates.
You'll want to do something like this (assuming that your date variable is named "date"):
use dataset_b
merge 1:1 date using dataset_a, keep(master) nogen
which will drop all observations from dataset_b with a date which is found in dataset_a. Note that if the same date may appear multiple times in dataset_b, then you'll need to replace 1:1 with m:1. I'm assuming that date is unique in dataset_a, but since you're only using this as a lookup table, if this is not the case, then you can just make a copy of dataset_a where duplicate dates have been excluded.
-- Phil
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