Re: st: RE: How to create sum of variables by time and space

["Ahmedov, Zafarbek" <zafar_ahmed@neo.tamu.edu>]

Nick,

Thanks a lot for your help.

Zafar

----- Original Message -----
From: "Nick Cox" <n.j.cox@durham.ac.uk>
To: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, June 8, 2011 1:07:50 PM GMT -06:00 US/Canada Central
Subject: RE: st: RE: How to create sum of variables by time and space

I didn't suggest that you typed that. I suggested that you read the help for -egen-. Both syntax and examples show that you need to specify the -egen- command and also that you can only work on one variable at a time, for example 

bysort location year month : egen total_tons = total(tons) 

Your aim is to "get the summary statistics", which leaves lots of scope for doing that in different ways. Other commands that might be what you want include -collapse- and -tabstat-. 

Nick 
n.j.cox@durham.ac.uk 

Ahmedov, Zafarbek


I tried "total(.)" but it didn't work with "by varlist:". I used the following code:

. sort location year month
. by location year month: total(Tons Number_of_Barges)

Do you have another suggestion? Thanks.

From: "Nick Cox" <n.j.cox@durham.ac.uk>

. help egen 

Ahmedov, Zafarbek

I'm using Stata 11. I have a data table with 5 variables (columns)and over 500,000 observations. Two of them are time (Year, Month) variables and one location (Location) variable. I am trying to get the sum of the other two variables (Tons, Number_of_Barges) by location and time. 

I tried to sort the data and get the summary statistics, but it didn't produce the desired result. I typed the following codes:

sort location year month
by location year month: summarize(Tons Number_of_Barges)


The problem with this code is, it didn't give the totals. I would greatly appreciate if you can offer any help or advise.

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