Re: st: parsing a variable positionally

[Rufus Peabody <rufus.peabody@gmail.com>]

Thanks a lot Nick.  The second option worked like a charm!

On Jun 3, 2008, at 5:55 AM, Nick Cox wrote:

> Phil is right that -substr()- is the main tool for parsing (string)
> variables positionally. -split- is only for situations in which you  
> have
> parsing characters.
>
> I once tried to think up a command that that would be a wrapper for
> repeated -substr()- and had just as much flexibility and simpler  
> syntax,
> but decided that the quest was futile.
>
> But given integer variables say -monthday- and -year-, you have other
> methods open to you.
>
> I guess that dates like 15 October and 31 December are held as 1015  
> and
> 1231. (That being so, you do not want to parse after the first
> character.)
>
> 1. Concatenate -monthday- and -year- (using -egen, concat()-, for
> example) and apply -date()-.
>
> Or
>
> 2. gen dailydate = mdy(floor(monthday/100), mod(monthday, 100), year)
>
> For the last, consider 1231. The monthly part is 12, and the daily  
> part
> is 31. The monthly part is thus floor(monthday/100) or int(monthday/ 
> 100)
> and the daily part is the remainder mod(monthday, 100).
>
>
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Philip Ryan
> Sent: 03 June 2008 09:35
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: parsing a variable positionally
>
> <sacrifice>
>
> the  substr()  string function might be useful.
>
> Phil
>
>  At 01:51 PM 3/06/2008, you wrote:
>
> > Hey all,
> >
> > I'm trying to convert a variable into a date.  Ordinarily, this would
> > be simple using Stata's date() functions, but one of my variables
> > contains both month and date (i.e. 403 is April 3rd), while another
> > contains year.  I'm trying to split the month+date variable into two
> > variables by parsing after the first character.  I tried converting
> > the variable to a string and using the "split" command, but it does
> > not allow me to parse positionally; it merely allows me to specify a
> > parsing character.  Is there a way to parse by position?
> >
> > Thanks,
> >
> > Rufus
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