Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: selecting variables by their format


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   RE: st: selecting variables by their format
Date   Thu, 15 Sep 2005 10:28:28 +0100

An observation in Stata is one row of your dataset, 
otherwise known as a case or record. 

A string is empty if it contains no 
characters and so is represented by "". 

Thus if I read in the auto dataset 
and ask for a listing 

. l if rep78 == 6 

I will get no result as there are 
no such observations. This is 
different from having some observations
which for a string variable just 
contain an empty string "". 

It's the difference between having no 
boxes and some boxes that happen to 
be empty. 

Nick 
[email protected] 

TEWODAJ MOGUES
 
> I'm not sufficiently familiar with stata-specific language, 

Nick Cox 

> "No observations" is here non-Stata language 
> for "all missing", meaning all empty strings. 

*
*   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/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index