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From |
Grace Jessie <gracejessie@hotmail.com> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: string function |

Date |
Wed, 24 Aug 2011 13:15:03 +0000 |

OK. Thanks. Grace ---------------------------------------- > Date: Wed, 24 Aug 2011 13:21:14 +0100 > Subject: Re: st: string function > From: njcoxstata@gmail.com > To: statalist@hsphsun2.harvard.edu > > To correct a typo: > > For all, the initialisation should be to 1. > > gen found = 1 > > qui foreach letter in s o m e t h i n g { > replace found = min(found, strpos(strvar, "`letter'") > 0) > } > > That is: the logic is to assume initially that all are present; if any > one is absent you change your mind. You can also do it this way > > gen found = 1 > qui foreach letter in s o m e t h i n g { > replace found = 0 if strpos(strvar, "`letter'") == 0 > } > > Also, in this solution "letter" is just an name that makes sense for letters. > > gen found = 1 > qui foreach pkg in Stata SAS SPSS { > replace found = 0 if strpos(strvar, "`pkg'") == 0 > } > > 2011/8/24 Grace Jessie <gracejessie@hotmail.com>: > > 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? > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: string function***From:*Grace Jessie <gracejessie@hotmail.com>

**Re: st: string function***From:*Nick Cox <njcoxstata@gmail.com>

**RE: st: string function***From:*Grace Jessie <gracejessie@hotmail.com>

**Re: st: string function***From:*Nick Cox <njcoxstata@gmail.com>

**RE: st: string function***From:*Grace Jessie <gracejessie@hotmail.com>

**Re: st: string function***From:*Nick Cox <njcoxstata@gmail.com>

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