# Re: st: RE: how to use lag function to create sequential number

 From mzhang@nd.edu To statalist@hsphsun2.harvard.edu Subject Re: st: RE: how to use lag function to create sequential number Date Sun, 11 Sep 2005 13:36:46 -0500

```Sorry I did not state my question well. there are different racial groups in my
sample. What i want to do is to give each racial group a sequential number.
for example, I have 17 whites, 5 blacks and 7 others. then the value of the
sequential variable I created would be: 1 2 3....17 for whites; 1 2 ...5 for
blacks;
1 2 ....7 for others. what I was originally thinking is:

gen sequence=1
replace sequcence=sequence+1 if l.race==race

However, this does not work out as I thought.

Min

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

> I am not aware of a lag function, i.e. -lag()-, in Stata. There is
> a lag operator L. but that is not appropriate for your purpose.
>
> You may be in search of
>
> bysort race : gen id = _n
>
> or
>
> bysort race : egen id = seq()
>
> although note that the labelling produced is essentially arbitrary
> in either case.
>
> Nick
> n.j.cox@durham.ac.uk
>
> mzhang@nd.edu
>
> > for example, there are 17 people who have the same ethnicity.
> > If I want to give
> > them a sequential number 1 2 3..........17, how can I use lag
> > function to do this?
>
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```