[Limdep Nlogit List] Re: CREATING AN UNDEFINED VARIABLE?

[William Greene]

Gail.  Don't put anything there.  If MIN doesn't already exist, then
when empl does not equal 1, this command
create; if (empl=1) min=mwcatsum $
will put a missing value (-999) in place.
/Bill Greene

************************************************
Professor William Greene
Department of Economics
Stern School of Business
New York University
44 West 4th St., Rm. 7-78
New York, NY   10012
Ph. 212.998.0876
Fax. 212.995.4218
URL. http://www.stern.nyu.edu/~wgreene
Email. wgreene at stern.nyu.edu
************************************************

----- Original Message -----
From: Gail Pacheco <gail.pacheco at aut.ac.nz>
Date: Wednesday, June 6, 2007 9:47 pm
Subject: [Limdep Nlogit List] Re: CREATING AN UNDEFINED VARIABLE?

> Hi
> i am wanting to create a variable that is only defined for a 
> subgroup of
> the total sample, at the moment my coding is:
> create; if (empl=1) min=mwcatsum;
> if (empl=0) min=???$
> 
> i am not sure what to put in place of the question marks? When 
> empl=1, i
> want the variable min to equal mwcatsum. But when empl is 0, i 
> want the
> variable min to be undefined.
> I am using these variables in a sample selection model.
> 
> Any help would be much appreciated
> 
> thanks
> 
> 
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> Gail Pacheco
> Senior Lecturer - Economics
> Faculty of Business
> AUT University
> gail.pacheco at aut.ac.nz
> 64-9-9219999 ext 5708
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