Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: getting Stata to read a bizarre sequence of dates
Date   Wed, 13 Jun 2012 08:45:58 +0100

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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index