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Re: st: any idea?
From
Eric Booth <[email protected]>
To
[email protected]
Subject
Re: st: any idea?
Date
Sun, 5 Jan 2014 15:03:38 -0600
<>
The Stata Journal link you mention that Nick sent you works for me. The title of the article is "Stata tip 71: The problem of split identity, or how to group dyads” by Nick J. Cox, so maybe you can google that title if your browser isn’t navigating to it properly.
Your example dataset doesn’t align with your desired dataset.
How do we know what is x and what is j in the first 20 obs of your example data (see below) (also note the Statalist FAQ about not sending attachments) ?
You need some kind of identifier that ties, for example, obs or id 1 (even though it’s missing) to the other right side femur observation of interest (is it id 7 or id 9 or ??).
**your example data:
id type side length
1 femur right
2 femur left
3 femur right
4 femur left
5 femur right 373
6 femur left 416
7 femur right 138
8 femur left
9 femur right 270
10 femur left
11 femur left
12 femur right
13 femur left
14 femur right
15 femur left 281
16 femur right
17 femur left 160
18 femur left
19 femur right
20 femur left
We can’t just sort by ‘type’ and ‘side’ to get a dataset of the same structure as you presented initially, so I think you need to provide more information about this. (also, if the rule is, as you imply, to sort by type and side and then subtract every third observation from each other then what do we do with missing 'length' and missing ‘side’?)
If the rule is that id 1 and id 2 are a pair then whey does the left/right ordering suddenly change starting around id 17?
- Eric
On Jan 5, 2014, at 2:46 PM, Y.R.E. Retamal <[email protected]> wrote:
> Dear Guys
>
> Some weeks ago, Red Owl and Nick helped me with some loops for my work. I have tried to run some suggestion in my dataset, but I had some difficulties.
> I give you the basic structure of my dataset and my question:
>
> I want to create some new variables containing the difference between the length of two individuals from different groups:
>
> id side length newvar1 newvar2 newvar3
> 1 right x x-j x-k x-l
> 2 right y y-j y-k y-l
> 3 right z z-j z-k z-l
> 4 left j j-x j-y j-z
> 5 left k k-x k-y k-z
> 6 left l l-x l-y l-z
>
> Red Owl suggested me following this example:
>
>>>> *** BEGIN CODE ***
>>>> * Build demo data set.
>>>> clear
>>>> * Length is capitalized to distinguish from length().
>>>> input id str5(side) Length
>>>> 1 right 10
>>>> 2 right 15
>>>> 3 right 11
>>>> 4 left 13
>>>> 5 left 10
>>>> 6 left 12
>>>> end
>>>> gen byte newvar1 = .
>>>> forval i = 1/3 {
>>>> replace newvar1 = Length[`i'] - Length[4] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar1 = Length[`i'] - Length[1] in `i'
>>>> }
>>>> gen byte newvar2 = .
>>>> forval i = 1/3 {
>>>> replace newvar2 = Length[`i'] - Length[5] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar2 = Length[`i'] - Length[2] in `i'
>>>> }
>>>> gen byte newvar3 = .
>>>> forval i = 1/3 {
>>>> replace newvar3 = Length[`i'] - Length[6] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar3 = Length[`i'] - Length[3] in `i'
>>>> }
>>>> list, noobs sep(0)
>>>> *** END CODE ***
>
> However, my dataset is much more longer and is difficult to perform it.
> I hope you can help me giving me more ideas.
> I send you an extract of my dataset in .xlsx format
> Also, the webpage suggested by Nick to review the discussion about the topic (http://www.stata-journal.com/sjpdf.html?articlenum=dm0043) redirects me to a non-sense file to download. Please give me the number of the journal to read the discussion.
>
> Happy new year to all of you
>
> Rodrigo
>
>
> On 2013-12-15 22:39, Y.R.E. Retamal wrote:
>> Dear Red Owl and Nick
>> Thank you very much for your response. The code works perfectly, just as I need.
>> Best wishes
>> Rodrigo
>> On 2013-12-14 22:31, Nick Cox wrote:
>>> In addition to Red's helpful suggestions, note that technique for such
>>> paired data was discussed in
>>> http://www.stata-journal.com/sjpdf.html?articlenum=dm0043
>>> which is publicly accessible. The problem is that the identifiers in
>>> Rodrigo's example appear to make little sense. How is Stata expected
>>> to know that 1 and 4, 2 and 5, 3 and 6 are paired? Perhaps the
>>> structure of the dataset is clearer in practice. If so, basic
>>> calculations are just a couple of lines or so.
>>> Nick
>>> [email protected]
>>> On 14 December 2013 15:33, Red Owl <[email protected]> wrote:
>>>> Rodrigo,
>>>> The following code demonstrates an approach with basic loops.
>>>> It could be made more efficient with a different loop
>>>> structure, but this approach may be more informative.
>>>> *** BEGIN CODE ***
>>>> * Build demo data set.
>>>> clear
>>>> * Length is capitalized to distinguish from length().
>>>> input id str5(side) Length
>>>> 1 right 10
>>>> 2 right 15
>>>> 3 right 11
>>>> 4 left 13
>>>> 5 left 10
>>>> 6 left 12
>>>> end
>>>> gen byte newvar1 = .
>>>> forval i = 1/3 {
>>>> replace newvar1 = Length[`i'] - Length[4] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar1 = Length[`i'] - Length[1] in `i'
>>>> }
>>>> gen byte newvar2 = .
>>>> forval i = 1/3 {
>>>> replace newvar2 = Length[`i'] - Length[5] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar2 = Length[`i'] - Length[2] in `i'
>>>> }
>>>> gen byte newvar3 = .
>>>> forval i = 1/3 {
>>>> replace newvar3 = Length[`i'] - Length[6] in `i'
>>>> }
>>>> forval i = 4/6 {
>>>> replace newvar3 = Length[`i'] - Length[3] in `i'
>>>> }
>>>> list, noobs sep(0)
>>>> *** END CODE ***
>>>> Good luck.
>>>> Red Owl
>>>> [email protected]
>>>>> Y.R.E. Retamal" <[email protected]> Sat, 14 Dec 2013 12:08:42:
>>>>> Dear list
>>>>> I am very complicated trying to perform an analysis using STATA and I
>>>> cannot find the way. Maybe you could help me. I want to create some new
>>>> variables containing the difference between the length of two
>>>> individuals from different groups:
>>>>> id side length newvar1 newvar2 newvar3
>>>>> 1 right x x-j x-k x-l
>>>>> 2 right y y-j y-k y-l
>>>>> 3 right z z-j z-k z-l
>>>>> 4 left j j-x j-y j-z
>>>>> 5 left k k-x k-y k-z
>>>>> 6 left l l-x l-y l-z
>>>>> I do not know if I do explain myself clearly, the individuals are
>>>> bones (clavicles, for example), so it is possible that some right
>>>> clavicles pair-match with left clavicles, following the idea that an
>>>> individual has bone of similar length.
>>>>> Any help could bring me a light!
>>>>> Best wishes
>>>>> Rodrigo
>>>> *
>>>> * For searches and help try:
>>>> * http://www.stata.com/help.cgi?search
>>>> * http://www.stata.com/support/faqs/resources/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/faqs/resources/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/faqs/resources/statalist-faq/
>> * http://www.ats.ucla.edu/stat/stata/
> <example.xlsx>
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/