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Re: st:how to keep the overlapping variables as many as possible when combining data sets


From   Mitch Abdon <mitchaabdon@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st:how to keep the overlapping variables as many as possible when combining data sets
Date   Thu, 4 Nov 2010 15:04:34 +0800

Try the update option. See -help merge-.


On Thu, Nov 4, 2010 at 2:42 PM, Amanda Fu <mandy.fu1@gmail.com> wrote:
>
> Dear Statalisters,
>
> I was trying to use "merge" to combine the following two data sets:
>
> data set 1: (master data set)
> ------------------------
> id      v1              v2
> 1       12      b
> 2       45      5
> 3
> 4       111     r
> 5       144             c
> -----------------------
> data set 2: (using data set) , where v1 and v2 are overlapped with
> comparison to data set 1.
> -----------------------
> id      v1      v2      v3
> 1       12           m  8
> 2       45                      8
> 3       78              0       8
> 4       111             2       8
> 5                       3
> 6       8                       7
> ----------------------------
> The following data set is what I want to see after the combination. That is:
> When there are overlapping variables, if the values in the master data
> set is available, the one in the master data set is used. On the
> condition that the value in the master data set is missing, use the
> one in the using data set if it is available.
> ----------------------------goal data set
> id      v1      v2      v3
> 1       12            b 8
> 2       45              5       8
> 3       78              0       8
> 4       111             r       8
> 5       144         c
> 6       8                       7
> ----------------------------
> But when I tried to use ---merge id using "2"----, the result is that
> for the overlapping variables only the values in the master data set
> are kept as following:
> ----------------------------merged data set
> id      v1      v2      v3
> 1       12            b 8
> 2       45              5       8
> 3                               8
> 4       111             r       8
> 5       144         c
> 6       8                       7
> ----------------------------
> May I know how I can get the goal data set using merge? Thanks for your time!
>
> Best wishes,
> Amanda Fu
> *
> *   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/



--
Best,
Mitch


Arnelyn Abdon
Mobile: +639178034402
http://statadaily.wordpress.com

*
*   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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