# st: Re: RE: Creating a variable (cumulative revenue by title)

 From "Martin Weiss" To Subject st: Re: RE: Creating a variable (cumulative revenue by title) Date Tue, 10 Feb 2009 21:56:28 +0100

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"I take it that references to -wkndrev- in your examples are typos. "

As are the ones to "week"... Grrrr...

HTH
```
Martin _______________________ ----- Original Message ----- From: "Nick Cox" <n.j.cox@durham.ac.uk>
```To: <statalist@hsphsun2.harvard.edu>
Sent: Tuesday, February 10, 2009 9:53 PM
Subject: st: RE: Creating a variable (cumulative revenue by title)

```
I take it that references to -wkndrev- in your examples are typos. Here is one way to do it: bysort title wk : egen crevall = total(wkrev) by title wk : gen tag = _n == 1 by title : replace crevall = sum(tag * crevall) Nick n.j.cox@durham.ac.uk
```Mike Kim

I have a question about creating a variable. The structure of my data is
```
a little complicated. Here is an example.
```
wk title country wkrev crevc wkrevall crevall
1     X     A         10     10    10     10
2     X     A         20     30     20     30
4     X     A         30     60     30     60
5     X     B         40     40     40     100
1     Y     C         10     10     30     30
1     Y     D         20     20     30     30
2     Y     C         30     40     70     100
2     Y     D         40     60     70     100
4     Y     E         50     50     50     150

wk=week
wkrev=weekly revenue
crevc=cumulative revenue from each country up to the week (by title)
wkrevall=weekly revenue from all countries for each week (by title)
crevall=cumulative revenue from all country up to the week (by title)

My question is: how can I create the last variable "crevall"?

I created 'crevc' and 'wkrevall' by the following:

sort title country week
by title country: gen crevc=sum(wkndrev)

sort title week country
by title week: egen wkrevall=total(wkndrev)

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```
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