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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]
*
* 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/
