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From |
Nick Cox <njcoxstata@gmail.com> |

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

Subject |
Re: st: Looping over datetimes for simultaneous variable generation |

Date |
Thu, 3 Oct 2013 10:48:13 +0100 |

There are several problems evident here, and I guess some latent too. You don't refer to any `datetime' macro within the loop, so at best it would do the same things, regardless of the loop. The syntax ' ' means nothing to Stata. You may wish to evaluate numeric constants on the fly, for which the syntax would be something like `= tc(19aug2012 0:00:00)’ The constant tc(00:05:00) seems unlikely to be what you intend. For an arbitrary numlist you need -foreach- not -forvalues-. Those points aside, a better strategy might to explain what you want to calculate, with enough about your data and some example data for people to follow. Nick njcoxstata@gmail.com On 3 October 2013 10:18, Paul Balcombe <paul.balcombe@postgrad.manchester.ac.uk> wrote: > I have a timeseries data set and I want to generate a number of variables that are conditional on each other and their previous values, so I want to create a value for the set of variables at each time period in my data. I thought I should use a forvalues command, but this is new to me and I have so far been unsuccessful: invalid syntax. below is the command I wish to make: > > forvalues datetime= ‘tc(19aug2012 00:00:00)’ (‘tc(00:05:00)’) ‘tc(18aug2013 23:00:00)’ { > replace seen=seen[_n-1] if seen==. & seen3[_n-1]<seen[_n-1] > replace segaspow=segaspow[_n-1] if seen==. & seen3[_n-1]<seen[_n-1] > replace seen2=seen2[_n-1] if seen==. & seen3[_n-1]<seen[_n-1] > replace seen3=seen2+seen3[_n-1] if seen==. & seen3[_n-1]<seen[_n-1] > } > > I may be describing the datetime functions incorrectly. > Thanks, > Paul > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/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/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Looping over datetimes for simultaneous variable generation***From:*Paul Balcombe <paul.balcombe@postgrad.manchester.ac.uk>

**References**:**st: Looping over datetimes for simultaneous variable generation***From:*Paul Balcombe <paul.balcombe@postgrad.manchester.ac.uk>

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