Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: pairing unpaired data [was: Re: st: any idea?]
From
"Y.R.E. Retamal" <[email protected]>
To
[email protected]
Subject
Re: pairing unpaired data [was: Re: st: any idea?]
Date
Tue, 07 Jan 2014 19:20:05 +0000
Dear Nick
Thanks a lot for your soon response. The method is no more than showed.
I have to add other variables like width and height for the same bone.
So, if three variables match, probably both bones would be from the same
skeleton.
I would expect that many bones would not match between them, so I could
discard them being from the same skeleton. Problems would appear if e.g.
a right bone matches with more than one left bone. But at least I could
simplify the work and after I could focus on problematic cases.
Rodrigo
On 2014-01-07 18:49, Nick Cox wrote:
I changed the thread title, which was not informative.
You need a method. Some predictable pitfalls are that for some bones
there is no acceptable match and that others there could be two or
more acceptable matches. I don't think there is a canned solution
independent of your spelling out what the method is.
Nick
[email protected]
On 7 January 2014 18:20, Y.R.E. Retamal <[email protected]> wrote:
Thank you very much Eric and Nick for the advices.
I will try to give a clearer idea of what want to do:
For example I have the following database of human bones. I removed
missing
values of length for a better understanding:
id type side length id type side length
1 femur left 18 21 humerus left 13
2 femur left 65.85 22 humerus left 56
3 femur left 69.1 23 humerus left 92
4 femur left 130 24 humerus left 126
5 femur left 131.2 25 humerus left 154
6 femur left 143 26 humerus left 170
7 femur left 145 27 humerus left 198
8 femur left 160 28 humerus left 228
9 femur left 183 29 humerus left 230
10 femur left 200 30 humerus left 232
11 femur right 28 31 humerus right 238
12 femur right 80 32 humerus right 10
13 femur right 96.5 33 humerus right 66
14 femur right 126 34 humerus right 123
15 femur right 127 35 humerus right 128
16 femur right 128 36 humerus right 143
17 femur right 138 37 humerus right 200
18 femur right 146 38 humerus right 228
19 femur right 148 39 humerus right 230
20 femur right 200 40 humerus right 241
These data belong to a commingled skeletal collection and some right
bones
(femurs and humerus respectively) should match with a left bone, but I
do
not know which bones match. Following the idea that a right bone from
a same
skeleton should have the same length (approximately) with its
respective
left bone, I want to subtract each right femur to each left femur,
with the
aim to find which right femur matches with a left femur, i.e. have the
same
or almost the same length, so the subtraction would be zero or near
zero.
The same proceeding with the humerus (and other bones).
If you have any idea to perform this, please let me know.
Rodrigo
Best wishes
Rodrigo
On 2014-01-05 23:54, Nick Cox wrote:
<>
Eric Booth gives very good advice.
Your problem with the link to the Stata Journal file you were
directed
to me may be just that you didn't step past the standard material
bundled with every reprint file.
Nick
[email protected]
On 5 January 2014 21:03, Eric Booth <[email protected]> wrote:
<>
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/
*
* 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/
*
* 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/