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From |
"Martin Weiss" <martin.weiss1@gmx.de> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: forvalues and _N |

Date |
Fri, 10 Oct 2008 21:56:08 +0200 |

HTH Martin _______________________

To: <statalist@hsphsun2.harvard.edu> Sent: Friday, October 10, 2008 9:02 PM Subject: Re: st: forvalues and _N

Thanks Nick and Martin, although I don't see this in either -help macro-or -help variables- ... unless it's the uninterpretable (to me)"[...] `expansion_optr' [...]"in -help macro- (FYI: Stata 9.2). I'm guessing that it IS in [P] Macro,but I frankly can't afford the manuals and wish Stata would make themavailable free online like SAS or on the install DVD like SPSS or at areasonable price in PDF form online which I know is one of those thingsyou're not supposed to talk about on Statalist. Grrr.Michael Nick Cox wrote:I think what Michael wants to know is documented better at -help macro-. `=exp' where exp is an expression lets you evaluate an expression on thefly and use its result. `=2 + 2' would be in these terms: the expressionis 2 + 2; Stata wouldevaluate that; and the command would see 4. As the example implies, theexpression can be a single item such as _N. This has been in Stata since(I think) sometime during Stata 7 but wasnot documented until Stata 8. There is a discussion within SJ-3-2 pr0009. . . . . . . . . . . . . Speaking Stata: Problems withlists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox Q2/03 SJ 3(2):185--202 (no commands) discusses ways of working through lists held in macros which is visible under the 3-year rule. Nickn.j.cox@durham.ac.uk P.S. The help and the manuals are, as always, thefirst documentation tothink of. Typically, the FAQs fill in some odd gaps or fill out some tricky topics. Martin Weiss see -help _variables-. The equal sign evaluates this -expression- so no need for any -macro-... Michael I. LichterWhoa! This works even though `=_N' is clearly not a macro. Is this anundocumented feature, or is it a "real" part of Stata that will stickaround? I'm sorry if this is discussed somewhere in the FAQ -- I havenoidea how to search for it.Philip Ryan wrote:Try: forvalues i = 1/`=_N' { .... }* * 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/-- Michael I. Lichter, Ph.D. Research Assistant Professor & NRSA Fellow UB Department of Family Medicine / Primary Care Research Institute UB Clinical Center, 462 Grider Street, Buffalo, NY 14215 Office: CC 125 / Phone: 716-898-4751 / E-Mail: mlichter@buffalo.edu * * 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/

**References**:**st: forvalues and _N***From:*"Bastian Steingros" <Steingros@gmx.de>

**Re: st: forvalues and _N***From:*Philip Ryan <philip.ryan@adelaide.edu.au>

**Re: st: forvalues and _N***From:*"Michael I. Lichter" <mlichter@buffalo.edu>

**Re: st: forvalues and _N***From:*"Martin Weiss" <martin.weiss1@gmx.de>

**RE: st: forvalues and _N***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: forvalues and _N***From:*"Michael I. Lichter" <mlichter@buffalo.edu>

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