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RE: st: string function


From   Grace Jessie <gracejessie@hotmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: string function
Date   Wed, 24 Aug 2011 11:50:09 +0000

OK,thank you, Nick.
Grace

----------------------------------------
> Date: Wed, 24 Aug 2011 12:37:23 +0100
> Subject: Re: st: string function
> From: njcoxstata@gmail.com
> To: statalist@hsphsun2.harvard.edu
>
> I just said that they _could_ be written.
>
> At that time, I had forgotten about -egen- solutions for your first
> problem in -egenmore- (SSC). Both of those solutions (by Nick Winter
> and myself) overlooked what now seems to me a cleaner solution using
> -subinstr()- and -length()-. See also
>
> <http://statadaily.wordpress.com/2011/01/20/counting-occurrence-of-strings-within-strings/>
>
> and my Speaking Stata column in SJ 11(1) 2011 for discussion.
>
> I am not aware of coded -egen- solutions for your other problems.
>
> I imagine that they would just be wrappers for those -foreach- loops,
> with no gain in efficiency or even comprehensibility.
>
> I'm setting them as an exercise for homework.
>
> Nick
>
> 2011/8/24 Grace Jessie <gracejessie@hotmail.com>:
> > Nick,
> > thank you.
> > Counld you please also tell me the -egen- solution for my questions?
> >
> > Grace
> >
> > ----------------------------------------
> >> Date: Wed, 24 Aug 2011 11:59:19 +0100
> >> Subject: Re: st: string function
> >> From: njcoxstata@gmail.com
> >> To: statalist@hsphsun2.harvard.edu
> >>
> >> Solutions to all these could be written as -egen- functions or Mata functions.
> >>
> >> Here I focus on "official Stata only" solutions.
> >>
> >> First question is discussed in
> >>
> >> Nicholas J. Cox
> >> Stata tip 98: Counting substrings within strings
> >> The Stata Journal 11(2): 318-320
> >>
> >> length("abcdaf") - length(subinstr("abcdaf", "a", "", .))
> >>
> >> Last two questions
> >>
> >> any of "a", "b", "c"
> >>
> >> max(strpos("abcdaf","a"), strpos("abcdaf", "b"), strpos("abcdaf", "c")) > 0
> >>
> >> all of "a", "b", "c"
> >>
> >> min(strpos("abcdaf","a"), strpos("abcdaf", "b"), strpos("abcdaf", "c")) > 0
> >>
> >> If you had a long list of candidates, I would do something like this:
> >>
> >> gen found = 0
> >>
> >> qui foreach letter in s o m e t h i n g {
> >> replace found = max(found, strpos(strvar, "`letter'") > 0)
> >> }
> >>
> >> where for "max" substitute "min" as needed.
> >>
> >> The mapping max <-> any, min <-> all is discussed in
> >> http://www.stata.com/support/faqs/data/anyall.html
> >>
> >> Nick
> >>
> >> 2011/8/24 Grace Jessie <gracejessie@hotmail.com>:
> >>
> >> > How to count how many times a substring appears in a string?
> >> > For example,
> >> > function("abcdaf","a")=2
> >> >
> >> > And, how to check if a string variable has certain substrings?
> >> > With regard to this, I want to ask two functions.
> >> > For example,
> >> > function("abcdaf","a","b","c")
> >> > One of what I want to do is to return 1 if a or b or c is included in "abcdaf", ;
> >> > the other is to return 1 if a, b and c are included in "abcdaf".
> >> > Could anyone tell me the correct functions for thoes above?
> >> *
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> >
>
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