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From |
Jeph Herrin <jeph.herrin@yale.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: -word()- with non space separator |

Date |
Wed, 23 Sep 2009 20:58:01 -0400 |

You are right. Thing is, I know the maximum - the number of possible values is contained in information that is attached to each variable. So my method and yours work fine. So my objection was totally unjustified. Jeph Nick Cox wrote:

Not knowing the highest value in advance would bite equally hard with the method in your previous post, which works from 1 upwards to aspecified maximum, so that objection seems unconvincing to me.Nickn.j.cox@durham.ac.ukJeph Herrin Thanks. I also thought of something like this, but didn't want to pursue it, if that makes sense. For one thing, I have literally thousands of variables and don't know ahead of time what the highest number I need is. As for the structure, it may not be the worst, but it is surely not the best. Nick Cox wrote:Another way to do it:clonevar work = myvarqui forval i = 29(-1)1 {gen myvar_`i' = strpos(work, "`i'") > 0replace work = subinstr(work, "`i'", "", .)}Here 29 is in general whatever highest number you need.In words, in addition to the -strpos()- logic,1. Work on a copy, because we're going to change it.2. Work downwards, from high values down to 1.3. Once you've checked for a longer string, zap it so that it doesn'tlater confuse the search for shorter strings.Incidentally, don't knock the format (or structure). When Uli KohlerandI wrote up the tricks we knew for multiple responses (in this sense),itwas pretty clear to us that all such formats or structures have somebigadvantages and disadvantages. Our efforts are accessible atFAQ . . . . . . . . . . . . . . . . . . . Dealing with multiple responses . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox andU.Kohler 4/05 How do I deal with multiple responses? http://www.stata.com/support/faqs/data/multresp.html SJ-3-1 pr0008 Speaking Stata: On structure & shape: the case ofmult.resp. . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox &U.Kohler Q1/03 SJ 3(1):81--99 (no commands) discussion of data manipulations for multiple response dataNickn.j.cox@durham.ac.ukJeph Herrin Solved - this does it: forv i=1/9 { gen byte myvar_`i'= regexm(myvar,"^`i':|:`i':|:`i'$") } Jeph Herrin wrote:I have a dataset in which many variables are in the most useless format imaginable. If a question has multiple checkboxes as possible answers, the response is stored as a string, with a number indicating each box checked and these numbers separated by colons. Thus: myvar 1:2:3:5:6:7:8:9 1:2:3:6 1:2:3:4:5:7:8:9 1:2:3:5:7:9 1:2:3:5:7:8:9 2:3:4:6:9 1:2:3:5:6:7:8:9 1:2:7:8:9 7:9 This variable takes 9 values, so I want to split into 9 different indicator variables, myvar_1-myvar_9, each indicating whether that number was selected. -split()- does not work, because of the differing number of values per string. That is, it produces myvar_1 which equals "7" for the last obs. So I am looking for a way to check whether a given string contains a given integer, which would allow me to forv i=1/9 { gen byte myvar_`i'= [`i' is in myvar list] } As long as there are just 9 values, I can use -strpos()- to check for the presence of the digit, but some of my variables run into tens and twenties, in which case eg searching for "1" returns true even if there is only "11". The only solutions I see are to first -split()- and then check all the new indicators, or run through a series of checks such as (matches "1:" but not ":1"). I don't like either: Is there a direct way to check to see if a given integer is in the list? I think there may be a regex solution, but my Perl programming days are so far behind me that I've not been able to come up with one.* * 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/ * * 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/

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**References**:**st: -word()- with non space separator***From:*Jeph Herrin <junk@spandrel.net>

**Re: st: -word()- with non space separator***From:*Jeph Herrin <junk@spandrel.net>

**RE: st: -word()- with non space separator***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: -word()- with non space separator***From:*Jeph Herrin <junk@spandrel.net>

**RE: st: -word()- with non space separator***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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