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RE: st: macro problem


From   Nick Cox <n.j.cox@durham.ac.uk>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: macro problem
Date   Mon, 11 Jun 2012 17:20:41 +0100

I agree with Richard's first point. 

His second point doesn't worry me. -if strpos(<arguments>)- is exactly equivalent to -if strpos(<arguments>) > 0-. Also, I don't think -strpos()- ever returns numeric missing. 

Here is a simple example that works: 

. l, sep(0)

     +-----------+
     |      var1 |
     |-----------|
  1. |      frog |
  2. |      toad |
  3. |      newt |
  4. |    newton |
  5. | toad hall |
  6. |    froggy |
     +-----------+

. gen match = 0

. foreach txt in "frog" "toad" "newt" {
  2. replace match = 1 if strpos(var1, "`txt'")
  3. }
(2 real changes made)
(2 real changes made)
(2 real changes made)

. l, sep(0)

     +-------------------+
     |      var1   match |
     |-------------------|
  1. |      frog       1 |
  2. |      toad       1 |
  3. |      newt       1 |
  4. |    newton       1 |
  5. | toad hall       1 |
  6. |    froggy       1 |
     +-------------------+


Nick 
n.j.cox@durham.ac.uk 


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Goldstein
Sent: 11 June 2012 16:59
To: statalist@hsphsun2.harvard.edu
Cc: Jeph Herrin
Subject: Re: st: macro problem

you don't make it clear about what doesn't work

but here is a guess: you are getting match=1 in all cases (or at least
all where strvar is not missing); remember, however, that strpos=0 if
"S" is not found; so, in addition to the quotes, etc., I guess you want
to ensure that strpos is >0 (and maybe <.)

Rich

On 6/11/12 11:50 AM, Jeph Herrin wrote:
> This should be trivial, but for some reason I cannot get it.
> 
> I have a string variable, and I have a list of string values I need to
> match against it. There are occasional trailing or leading characters in
> the variable, so I am using -strpos- to find matches. Thus
> 
>   local matchlist "string 1" "string 2"  "string 3" .... "string 55"
> 
>   gen byte match=0
>   foreach S in `matchlist' {
>         replace match = 1 if strpos(strvar,`S')
>   }
> 
> Now, I know I have got the quotes and macro evaluations wrong, but that
> is the problem: I've tried this many different ways, and yet cannot seem
> to find a combination that works. Any thoughts?
> 
> thanks,
> Jeph
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