On that point: while writing my post, I dodged the question of how to call
_N by its name. I probably should have said "system variable", as in -h
_variables-...
Martin
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Nick Cox
Sent: Monday, September 01, 2008 5:51 PM
To: [email protected]
Subject: st: RE: RE: Trouble with `=`_N'-1'
Just to underline Martin's analysis: the reference `_N' would be
appropriate if _N were the name of a local macro, but _N is not a local
macro.
Nick
[email protected]
Martin Weiss
Stata does not know what to do about `_N', so it evaluates to nothing.
The
whole -in- statement evaluates to - in -1 - which denotes the last
observation. Say -replace line = 5 in `=_N-1'- and it works fine. Now _N
is
well defined and the expression evaluates to the desired value. Note
that
you could have put - in -2 - to begin with, and would have saved
yourself
the trouble...
Ashim Kapoor
I wish to make a change in the 2nd last observation.
so I have : replace line = 5 in `=`_N'-1'
But this change the LAST observation! Am I doing something wrong?
funnily replace line = 5 if _n==_N-1 works fine!
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
