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RE: st: Beginner Q: 7mil obs - how to add variables


From   "Coleman, Greg" <greg.coleman@emc.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Beginner Q: 7mil obs - how to add variables
Date   Tue, 8 Oct 2013 20:02:23 +0000

Yes! You did. Thank you. I jumped the gun. A little more exploring showed me it created the new column, newvar, with the total distance for each tailnum repeated in the rows where tailnum occurred again. 


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Goldstein
Sent: Tuesday, October 08, 2013 3:37 PM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Beginner Q: 7mil obs - how to add variables

as far as I can understand you, what I sent gives you what you want (though Scott's answer does also and compresses several steps into 1)

the display command you used just shows the result in the first observation; did you look at the data? e.g., -browse tailnum distance
newvar-

to go the rest of the way to your graph:

sort tailnum
gr whatever if tailnum!=tailnum[_n-1]

or any of several other ways of reducing

Rich

On 10/8/13 3:25 PM, Coleman, Greg wrote:
> Thanks.
> That just gives me this:
> 
> 
> . egen newvar=total(distance), by(tailnum)
> 
> . display newvar
> 149899
> 
> Distance flown by airplane with tail number XXXXXX
> 
> I am trying to eventually graph the top N planes by distance flown.
> 
> I am getting close (I think) to understanding some features, I can see this:
> 
> . bysort tailnum: sum distance
> 
> ----------------------------------------------------------------------
> ------------------------------------------------
> -> tailnum = 80009E
> 
>     Variable |       Obs        Mean    Std. Dev.       Min        Max
> -------------+--------------------------------------------------------
>     distance |      1959    452.6514    216.5128         56       1194
> 
> ----------------------------------------------------------------------
> ------------------------------------------------
> -> tailnum = 80019E
> 
>     Variable |       Obs        Mean    Std. Dev.       Min        Max
> -------------+--------------------------------------------------------
>     distance |      1906    446.2739    222.8244         56       1149
> 
> 
> But need the arithmetic sum of all the distances for each tailnumber.
> 
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu 
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard 
> Goldstein
> Sent: Tuesday, October 08, 2013 3:01 PM
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: Beginner Q: 7mil obs - how to add variables
> 
> not completely clear, but it looks like this will get you what you want:
> 
> egen newvar=total(Value), by(String)
> 
> Rich
> 
> On 10/8/13 2:46 PM, Coleman, Greg wrote:
>> Hi
>> My data has 7 million observations and 29 variables. About 10 of the 
>> variables are string, and I am trying to get some patterns of the 
>> numerical values which are related to the strings. To clarify,
>>
>> String                    Value
>> AB1234                 25
>> CDE789                 44
>> F9999                    126
>> CDE789                 10
>> AB1234                 3
>> F9999                    100
>>
>> I would like to get output that looks like the sum of values, per string:
>> AB1234 28
>> CDE789 54
>> F9999 226
>>
>> Some strings are just numbers, some are just letters, and some are a combination. 
>> Can anyone assist?
>> Thanks!
>> Greg
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