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Re: st: How to combine variables in network data - can I loop over stubs?


From   Brandon Olszewski <olszewski.brandon@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: How to combine variables in network data - can I loop over stubs?
Date   Wed, 20 Apr 2011 16:58:23 -0700

Thanks for the positive and prompt response, Nick!
I'll crunch on that tonight and try and make it work. Thanks for the
help reference, too.
And yes, the <0, 2, 3> thing was a typo. My apologies, as I know that
is not good etiquette.
Cheers,
Brandon

On Wed, Apr 20, 2011 at 4:45 PM, Nick Cox <njcoxstata@gmail.com> wrote:
> That may be your ideal syntax but the documentation for -foreach- is
> clear. There is no such legal form.
>
> foreach stub in AAA BBB {
> ...
> }
>
> is perfectly legal.
>
> To get a list of all such stubs, you could try:
>
> unab stubs : *_0
> local stubs : subinstr local stubs "_0" "", all
>
> See http://www.stata.com/support/faqs/data/reshape3.html for explanation.
>
> You can then go
>
> foreach stub of local stubs {
> ...
> }
>
> In short, good news: you don't need a new syntax. Existing syntaxes
> can be adopted.
>
> Your mapping 0, 1, 2 -> 0, 2, 3 seems a bit strange, but I assume
> that's a typo or a side-issue.
>
> Nick
>
> On Thu, Apr 21, 2011 at 12:23 AM, Brandon Olszewski
> <olszewski.brandon@gmail.com> wrote:
>
>> I have a -wide- social network data set that needs some cleaning. It
>> contains about 40 different projects, here named AAA, BBB, CCC, etc.
>> Each project is connected to every other project at some level, 0 =
>> “no familiarity”, 1 = “familiar”, and 2 = “works with a lot”. Rows
>> represent projects, and columns represent the level of familiarity a
>> project has with others. Here is what the data look like, then:
>>
>> project AAA_0   AAA_1   AAA_2   BBB_0   BBB_1   BBB_2
>> AAA                                                                                     1
>> BBB                     0
>> Etc.
>>
>> In the above example, project AAA knows B at a level 1 (familiar), and
>> project BBB reports not knowing project AAA (at a level 0).
>>
>> I want to create variables (total_AAA, total_BBB, etc.) that combine
>> columns with the same stub (“AAA”, “BBB”, etc.) so that one new column
>> represents the three old columns. The new column would contain a value
>> (0, 1, or 2) that was previously represented in wide format across
>> three columns. Searching the statalist, the following post is the
>> closest I found:
>> http://www.stata.com/statalist/archive/2007-03/msg00234.html.
>>
>> I’m thinking of using a -foreach- command to do it, but I think I
>> would need to loop the command over a stub, rather than a varname. I
>> also know how to use -renpfix- to change stub names. In my ideal
>> world, a solution would look like:
>>>>>
>> foreach stub of stubname AAA BBB{
>>        gen total`stub’=0
>>        replace total`stub’=2 if `stub’_1==1
>>        replace total`stub’=3 if `stub’_2==2
>>        }
>> keep project total*
>>>>>
>>
>> I've racked my brain with -reshape- and some other commands I know,
>> but the logic eludes me and I am still unsuccessful. Can anyone help
>> me?
>>
>
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