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Re: st: Drop Observations if Greater than A Particular Date


From   Lisa Wang <lhwang0925@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Drop Observations if Greater than A Particular Date
Date   Wed, 1 Aug 2012 08:25:36 +1000

Hi Steve,

Thank you for your advice and teaching me some new code as well. I am
new to Stata, so still trying (very hard) to learn! Also appreciate
how quickly you responded.

Many thanks,
Lisa

On Wed, Aug 1, 2012 at 8:17 AM, Steve Nakoneshny <scnakone@ucalgary.ca> wrote:
> Lisa,
>
> When you changed your date var to display as %td the only thing you changed was how you got to see it in your dataset, NOT the underlying number.
> Type -di date("20060720","YMD")- to see what the value for that date is given the date format you specified.
>
> You can write it out in two lines as:
> di date("20060720","YMD")
> drop if date > 17002
>
> Or more concisely as:
> drop if date > date("20060720","YMD")
>
>
> Steve
>
> On 2012-07-31, at 3:59 PM, Lisa Wang wrote:
>
>> Hi all,
>>
>> I have a simple problem but don't understand why it is currently not
>> working, so any help would be appreciated. I have imported data
>> (including dates) into Stata from a csv file and then ran code to
>> change it into %td format
>>
>> -generate edate = date(date, "YMD")           //translate string dates into lapsed dates
>> format edate %td
>> drop date
>> rename edate date
>> label variable date Date-
>>
>> I then would like to drop observations where the date is greater than
>> 20-07-2006. I did -drop if date>20072006- but that does not drop any
>> observations at all when I can see that there are instances where the
>> date is greater than this.
>>
>> Do I have to convert my 20-07-2006 back into lapsed dates, then how do
>> I work out what value this corresponds to? I would have thought it
>> would be easier than this.
>>
>> Thank you for your suggestions,
>> Lisa
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>
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