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From |
stef salvez <loggyedy@googlemail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: getting Stata to read a bizarre sequence of dates |

Date |
Fri, 15 Jun 2012 18:01:59 +0200 |

thank you NIck very much for one more time. (the problem with my pc has been resolved and am back with my proper name again) Again, i reallly thank you On 6/13/12, Nick Cox <n.j.cox@durham.ac.uk> wrote: > There are no contradictions here. Many dates round to the same value of > floor(dailydate/28). The rounded date does not remember what it was > originally. > > tsfill- only adds observations with missing values at times that were gaps. > It does not interpolate. > > Nick > n.j.cox@durham.ac.uk > > joales salbdralor > > > Thank you for your reply on my question > I want to comment on two things > > 1) You mentioned that > " There is a gap > at 638 as the following reveals. > > . format edate1 %td > > . tab edate1 > > edate1 | Freq. Percent Cum. > ------------+----------------------------------- > 23nov2008 | 2 14.29 14.29 > 28dec2008 | 2 14.29 28.57 > 25jan2009 | 2 14.29 42.86 > 22feb2009 | 2 14.29 57.14 > 29mar2009 | 2 14.29 71.43 > 26apr2009 | 2 14.29 85.71 > 24may2009 | 2 14.29 100.00 > ------------+----------------------------------- > Total | 14 100.00 > > . tab edate2 > > edate2 | Freq. Percent Cum. > ------------+----------------------------------- > 637 | 2 14.29 14.29 > 639 | 2 14.29 28.57 > 640 | 2 14.29 42.86 > 641 | 2 14.29 57.14 > 642 | 2 14.29 71.43 > 643 | 2 14.29 85.71 > 644 | 2 14.29 100.00 > ------------+----------------------------------- > Total | 14 100.00 > > But there is also another gap of 35 days going from 22/02/09 to > 29/03/09 which is not taken into account by the above table. Why is > this the case? > You can see the same problem by looking at the data editor after having > typed > > gen edate1 = date(dates1, "DM20Y") > gen edate2 = floor(edate1/28) > tsset id edate2 > tsfill, full > > 2) My opinion is that by using the -tsfill, full- as a solution to > "fix" the gap problem I do not gain much because even if I issue the > commands > > gen edate1 = date(dates1, "DM20Y") > gen edate2 = floor(edate1/28) > tsset id edate2 > tsfill, full > egen nonmiss = rownonmiss(id) > > and base my analysis on ..if rownonmiss(2) nothing will change. I > just sort out the data in a more clear way. As you mentioned, > interpolation may be the best solution > > thanks again > > > On 6/13/12, Nick Cox <njcoxstata@gmail.com> wrote: >> If "joales salbdralor" is really "stef salvez" what is going on? Do >> note the firm request that Statalist posters use their real names. >> >> If you have gaps in your data, most commands can cope. There is no >> catch-all solution, as whether gaps are a problem depends on what you >> want to do. Some kind of interpolation would be necessary for some >> commands to be used. >> >> Nick >> >> On Wed, Jun 13, 2012 at 8:31 AM, joales salbdralor >> <joalessakafiora@googlemail.com> wrote: >>> thanks Nick for your reply. you are right (as always) that Stata can >>> read these string dates and it is converting them to numeric dates. >>> The only problem that I have is how to avoid having the "with gaps" >>> comment, Put differently, how can I correct this problem?. Or is it ok >>> by just issuing the previously mentioned commands, that is: >>> >>> gen edate1 = date(dates1, "DM20Y") >>> gen edate2 = floor(edate1/28) >>> tsset id edate2 >>> >>> >>> Regarding your reasonable question why I am posting mysteriously >>> similar questions is that I want to play around with different and >>> "bizarre" sequence of dates as this is the first step if I want to >>> start doing correct data/econometric analysis . >>> >>> >>> >>> thank you very much again >>> >>> >>> On 6/13/12, Nick Cox <njcoxstata@gmail.com> wrote: >>>> You've posted numerous questions on this kind of data over the last >>>> few weeks, to which there have been numerous answers, so why you ask >>>> this question seems especially mysterious. >>>> >>>> First, Stata _is_ reading your string dates and it _is_ converting >>>> them to numeric dates. So the implication that Stata can't read these >>>> data is quite wrong. >>>> >>>> The only problem evident is that there is one gap in this dataset even >>>> when you restructure it as a series with spacing 28 days. >>>> >>>> So, what -tsset- reports is essentially "fair comment". There is a gap >>>> at 638 as the following reveals. >>>> >>>> . format edate1 %td >>>> >>>> . tab edate1 >>>> >>>> edate1 | Freq. Percent Cum. >>>> ------------+----------------------------------- >>>> 23nov2008 | 2 14.29 14.29 >>>> 28dec2008 | 2 14.29 28.57 >>>> 25jan2009 | 2 14.29 42.86 >>>> 22feb2009 | 2 14.29 57.14 >>>> 29mar2009 | 2 14.29 71.43 >>>> 26apr2009 | 2 14.29 85.71 >>>> 24may2009 | 2 14.29 100.00 >>>> ------------+----------------------------------- >>>> Total | 14 100.00 >>>> >>>> . tab edate2 >>>> >>>> edate2 | Freq. Percent Cum. >>>> ------------+----------------------------------- >>>> 637 | 2 14.29 14.29 >>>> 639 | 2 14.29 28.57 >>>> 640 | 2 14.29 42.86 >>>> 641 | 2 14.29 57.14 >>>> 642 | 2 14.29 71.43 >>>> 643 | 2 14.29 85.71 >>>> 644 | 2 14.29 100.00 >>>> ------------+----------------------------------- >>>> Total | 14 100.00 >>>> >>>> By the way, posting code that others can run is an excellent idea, but >>>> cut the -cd d:- which assumes that users have a d: drive, which may be >>>> quite wrong. >>>> >>>> Nick >>>> >>>> On Wed, Jun 13, 2012 at 12:37 AM, stef salvez <loggyedy@googlemail.com> >>>> wrote: >>>> >>>>> I have the following panel data set >>>>> >>>>> clear all >>>>> cd d:\ >>>>> input str8 (dates1) id >>>>> "23/11/08" 1 >>>>> "28/12/08" 1 >>>>> "25/01/09" 1 >>>>> "22/02/09" 1 >>>>> "29/03/09" 1 >>>>> "26/04/09" 1 >>>>> "24/05/09" 1 >>>>> "23/11/08" 2 >>>>> "28/12/08" 2 >>>>> "25/01/09" 2 >>>>> "22/02/09" 2 >>>>> "29/03/09" 2 >>>>> "26/04/09" 2 >>>>> "24/05/09" 2 >>>>> >>>>> end >>>>> >>>>> the difference (in days) between successive dates is 35 28 28 35 28 >>>>> 28 >>>>> >>>>> The problem is that I do not know how to convert these string dates >>>>> into numeric variables given the fact that I have 2 jumps (35 days) >>>>> if i issue the commands >>>>> >>>>> gen edate1 = date(dates1, "DM20Y") >>>>> gen edate2 = floor(edate1/28) >>>>> tsset id edate2 >>>>> >>>>> I get the following error message >>>>> >>>>> panel variable: id (strongly balanced) >>>>> time variable: edate2, 637 to 644, but with gaps >>>>> delta: 1 unit >>>>> >>>>> Is there any code that could fix that so as to get Stata to "read" >>>>> that "bizarre"sequence of dates? >> >> * >> * 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/ > > * > * 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: getting Stata to read a bizarre sequence of dates***From:*stef salvez <loggyedy@googlemail.com>

**Re: st: getting Stata to read a bizarre sequence of dates***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: getting Stata to read a bizarre sequence of dates***From:*joales salbdralor <joalessakafiora@googlemail.com>

**Re: st: getting Stata to read a bizarre sequence of dates***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: getting Stata to read a bizarre sequence of dates***From:*joales salbdralor <joalessakafiora@googlemail.com>

**RE: st: getting Stata to read a bizarre sequence of dates***From:*Nick Cox <n.j.cox@durham.ac.uk>

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