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# Re: st: Matrix zeros and ones

 From "Tribin Uribe, Ana" <[email protected]> To [email protected] Subject Re: st: Matrix zeros and ones Date Fri, 26 Aug 2011 18:49:53 -0400

```Thanks maarten I have everything with codes (friends and letters),
this is, a number for each one
(numbers are not in order). The problem is that the list of friends is
huge and also the list of letters,so to apply the command gen byte by
friend would be impossible. Do you have any suggestion on how to deal
with that?
Thank you very much

On Mon, Aug 22, 2011 at 8:20 AM, Maarten Buis <[email protected]> wrote:
> On Mon, Aug 22, 2011 at 1:59 PM, Tribin Uribe, Ana wrote:
>> I have  data  about  letters that have been sign by a group of people
>>
>> Letter   signatures
>> Letter1 Friend1
>> Letter2 Friend2 Friend3 Friend4 Friend5
>> Letter3 Friend4
>>
>> I want to create with this information  a matrix with zeros and ones,
>> like this one using information above
>>
>> Letter Friend1  Friend2  Friend3 Friend4 Friend5
>> Letter1 1 0 0 0 0
>> Letter2  0 1 1 1 1
>> Letter3  0 0 0 1 0
>
> *----------------------- begin example ---------------------
> clear
> input ///
> Letter  str31 signatures
> 1             "Friend1"
> 2             "Friend2 Friend3 Friend4 Friend5"
> 3             "Friend4"
> end
>
> gen byte friend1 = strpos(signatures, "Friend1") > 0
> gen byte friend2 = strpos(signatures, "Friend2") > 0
> gen byte friend3 = strpos(signatures, "Friend3") > 0
> gen byte friend4 = strpos(signatures, "Friend4") > 0
> gen byte friend5 = strpos(signatures, "Friend5") > 0
>
> l Letter friend*
> *--------------------- end example ------------------------
> (For more on examples I sent to the Statalist see:
> http://www.maartenbuis.nl/example_faq )
>
> There are however two things I would worry about: 1) Your data is
> stored as a string variable, and these can only contain 244 characters
> (including spaces). I can easily imagine letters signed by groups of
> people where that limit is surpassed. 2) When signing people can
> easily use other variations of their own name (Maarten, Maarten Buis,
> M. Buis, dr. M. Buis, Dr. M. Buis, dr. M.L. Buis, dr. M. L. Buis
> (extra space between M. and L.), Maarten Leendert Buis, Maarten L.
> Buis, etc. etc.). Even if people are consistent in the way they sign
> their name, the person that typed them in could easily make typos (an
> incomplete list of variations on my name that have appeared on this
> list is: Marteen, Maarteen, Maarrten, Martin). The strategy used above
> is very sensitive to such variations.
>
> Hope this helps,
> Maarten
>
> --------------------------
> Maarten L. Buis
> Institut fuer Soziologie
> Universitaet Tuebingen
> Wilhelmstrasse 36
> 72074 Tuebingen
> Germany
>
>
> http://www.maartenbuis.nl
> --------------------------
> *
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>

*
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```