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RE: st: date function
From
"Dherani, Mukesh" <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
RE: st: date function
Date
Tue, 6 Aug 2013 15:56:41 +0000
Thanks Nick. Yes, date was messed up somehow (mystery to me). Below is date in as I could see (date), after format %d (afterformat) and gen date1=date. This is why I was trying to view month and year after format.
date afterformat date1
19/02/200 19/02/2003 81
17/01/200 17/01/2003 24
03/01/200 03/01/2003 9
23/01/200 23/01/2003 46
03/01/200 03/01/2003 9
07/01/200 07/01/2003 97
10/01/200 10/01/2003 29
18/07/200 18/07/2003 44
25/04/200 25/04/2003 100
05/04/200 05/04/2004 35
03/01/200 03/01/2003 9
19/06/200 19/06/2003 51
13/06/200 13/06/2003 4
19/08/200 19/08/2003 102
30/05/200 30/05/2003 118
29/09/200 29/09/2003 38
26/12/200 26/12/2002 72
08/01/200 08/01/2003 73
26/09/200 26/09/2003 25
17/01/200 17/01/2003 24
20/06/200 20/06/2003 10
10/02/200 10/02/2004 125
25/08/200 25/08/2003 109
16/05/200 16/05/2003 42
20/02/200 20/02/2003 39
09/02/200 09/02/2004 85
14/05/200 14/05/2004 58
08/07/200 08/07/2003 7
16/07/200 16/07/2003 84
14/12/200 14/12/2003 31
BW,m
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Nick Cox
Sent: 06 August 2013 16:18
To: [email protected]
Subject: Re: st: date function
Working backwards:
1. Changing the format of anything has precisely no effect on what is stored, only on what is displayed. Thinking that "format" means "display format" and nothing else is crucial to understanding this.
There is a Tip spelling this out in excruciating detail.
http://www.stata-journal.com/article.html?article=dm0067
So no machinations with -format- will solve this problem.
2. My guess is that your -date- variable is thoroughly messed up and it was produced in some wild way. I guess further that you used
-encode- to convert a string variable into a numeric variable with labels. If you look at the dates that Stata thinks are stored they are all daily dates in 1960 and, moreover, the first such date in your sample is
03/01/2003 10 1 1960
and the last such date is
25/04/2003 10 4 1960
which is consistent with this guess. That is, the string "03/01/2003"
is the first alphabetically (alphanumerically) and the string "25/04/2003" is the last alphabetically in this sample and they, and the other dates, have been mapped to numbers. -encode- is totally clueless about dates and faced with dates it can only treat them like any other set of strings, the first alphabetically being mapped to 1, the second to 2, and so forth, regardless of the strings' meaning or content.
So, you must go back and recalculate your dates, using the -date()- function. Ironically, or otherwise, this is the title of your post, but you appear not to have used it.
As said, these are guesses, but I'd call them informed guesses.
The document to read first, second and third on dates is the help.
-help dates and times-.
Nick
[email protected]
On 6 August 2013 15:52, Dherani, Mukesh <[email protected]> wrote:
> I have a problem getting my date variable sorted. I have Date
> variable in = my data (float) and I want month and year extracted
> using
>
> gen month = month(date)..... same for day and yr.
> However, I am getting incorrect values for month and year (even day).
> I have also tried formatting month and year to %m and %ty, but to no avail.
> Any help appreciated... I am using Stata 10. [no luck with FAQ so far]
>
>
> date day month yr
> 19/02/2003 22 3 1960
> 17/01/2003 25 1 1960
> 03/01/2003 10 1 1960
> 23/01/2003 16 2 1960
> 03/01/2003 10 1 1960
> 07/01/2003 7 4 1960
> 10/01/2003 30 1 1960
> 18/07/2003 14 2 1960
> 25/04/2003 10 4 1960
> 05/04/2004 5 2 1960
> 03/01/2003 10 1 1960
> 19/06/2003 21 2 1960
> 13/06/2003 5 1 1960
> 19/08/2003 12 4 1960
>
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