[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

From |
"Nick Cox" <[email protected]> |

To |
<[email protected]> |

Subject |
st: RE: A question concerning Stata logic |

Date |
Thu, 1 Dec 2005 12:47:14 -0000 |

Consider . replace var3=var3[_n+1] if var3==. & _n<_N The restriction _n < _N only bites with the last value. In this example, it makes no difference, as a reference to var3[_N+1] is evaluated as missing, and so the restriction can be set on one side. In words, you are asking Stata to replace missing with the next value. Only in the case of var3[2] does this make any difference, but Stata is doing exactly what you asked. Perhaps the principle being missed is given by the title of a note by Roger Newson, one that is also stressed in various FAQs, including the one cited below. SJ-4-4 dm0008 Stata tip 13: generate and replace use the current sort order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R. Newson Q4/04 SJ 4(4):484--485 (no commands) tips for using generate and replace, which use the current sort order In addition what I think is your problem is discussed at length in FAQ . . . . . . . . . . . . . . . . . . . . . . . Replacing missing values 2/03 How can I replace missing values with previous or following nonmissing values? http://www.stata.com/support/faqs/data/missing.html Nick [email protected] Daniel Hoechle > Consider the following three identical variables to start with: > > var1 var2 var3 > . . . > . . . > . . . > 2 2 2 > 3 3 3 > 4 4 4 > . . . > . . . > . . . > > Typing > > . replace var2=var2[_n-1] if var2==. & _n>1 > . replace var3=var3[_n+1] if var3==. & _n<_N > > results in > > var1 var2 var3 > . . . > . . . > . . 2 > 2 2 2 > 3 3 3 > 4 4 4 > . 4 . > . 4 . > . 4 . > > > Why does Stata replace all three missings in the first case > but only the > first missing in the second case? Do I have to sort the dataset the > other way around in order to fill var3 in a similar way as var2 or is > there an easy workaround? * * 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/

- Prev by Date:
**st: RE: Creation of family id** - Next by Date:
**st: question for fixed effect model/random effect model** - Previous by thread:
**st: RE: Creation of family id** - Next by thread:
**st: question for fixed effect model/random effect model** - Index(es):

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