st: Re: Escaping left quote as argument of parse in split command

["Florian Kuhn" <florian@mail.utexas.edu>]

Thanks, Eric and Nick. A workaround it will be.
Florian

-----Original Message----- 
From: Nick Cox
Sent: Wednesday, April 04, 2012 3:23 AM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Escaping left quote as argument of parse in split command

I agree with Eric. This particular character is awkward for -split-
and a work-around like that shown in its help for the tab character
doesn't help.

A first-principles solution is also easy in this case:

. gen part1 = substr(id, 1, strpos(id, "`") - 1)

. gen part2 = substr(id, strpos(id, "`") + 1, .)

Nick

On Wed, Apr 4, 2012 at 5:29 AM, Eric Booth <eric.a.booth@gmail.com> wrote:

> I'm not sure how to get the parse option of -split- to accept the single 
> left quote, but you can get around it by using a function 
> like -subinstr()- to replace the left quote with something else and 
> then -split-, so:
>
> **
> replace id = subinstr(x, "`", "@", .)
> split id, parse("@")
> **
>
>
> P.S.
> The part of the split.ado file that is choking is (using trace):
>
>    - if `"`parse'"' == `""' | `"`parse'"' == `""""' {
>    = if `""`""' == `""' | `""`""' == `""""' {
> { required
>
> In trying to escape the single left quote in -split-, I had a copy/paste 
> error and accidentally ran:
>
>  split id, parse("\`\`"'')
>
> which curiously gave the error:
>
> "no room to add more variables
>    Up to 32,000 variables are currently allowed, although you could reset 
> the maximum using set maxvar; see help
>    memory.
> r(900); t=14.37 23:21:53"
>
>
> Since string functions, like subinstr(), can work with the single left 
> quote, it seems like it should be possible that -split- could work with it 
> as well (I say that without knowing anything about the internal mechanics 
> of the string functions like subinstr())

On Apr 3, 2012, at 10:45 PM, Florian Kuhn wrote:

> > in my dataset, I have a string variable “id” in which the left single 
> > quote ` is used to separate a first and second part of the id (the 
> > creators of the dataset were clearly not using Stata). For example, a 
> > typical entry in the column "id" would be 15`32. I am trying to recover 
> > both parts of the id as separate variables using the "split" command.
> >
> > However, escaping the backtick does not seem to work:
> > split id, parse("\`")
> > gives the error message:
> > { required
> > r(100);
> >
> > Am I missing something obvious here?

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