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From |
"David E Moore" <davem@hartman-group.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: RE: RE: RE: local variable and indexing into a variable |

Date |
Fri, 24 Jun 2005 09:12:07 -0700 |

Nick is, of course, absolutely correct. (NB, the last character is the lowercase el, not the number 1.) Moreover, he makes another point, albeit indirectly. That is, Stata often can get you to the result you want by more than one path, but one may take advantage of Stata features that offer significant efficiency gains. The moral of the story is it pays to think in Stata-ese. -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox Sent: Friday, June 24, 2005 12:59 AM To: statalist@hsphsun2.harvard.edu Subject: st: RE: RE: local variable and indexing into a variable What David suggests is fine and -- more to the point -- legal -- whereas what Florence tried is illegal. The way to see this is to look at the syntax diagram for -replace-, which makes it clear that a existing varname (only) can appear on the LHS of an equals sign. A quite different point is that David's suggestion obliges Stata to test every observation to see if _n == _N. replace `var' = 0 in l lets Stata go straight to the last observation. Nick n.j.cox@durham.ac.uk David E Moore > Stata prefers: > > replace `var' = 0 if _n==_N NEYMOTIN, FLORENCE > Hi, I tried typing: > > foreach var in x y { > replace `var'[_N]=0 > } > > then it considers [_N] a "weight" when clearly I want it to > just change the last > observation of > both x and y to be zeroes. > > alternatively, I tried the inner line as: ( replace > `var[_N]'=0 ) and then it > doesn't recognize > var[_N] and thinks that it is an entirely new local reference. > Is there a correct syntax here, or does it look like there is > some other sort of mistake in my coding ? * * 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/ * * 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/

**References**:**st: RE: RE: local variable and indexing into a variable***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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