st: Re: matching variable values

[evan roberts <eroberts@hist.umn.edu>]

Gregor Franz asked how to attach a mother's height to children's 
records when the mothers were identified by an ID number

sort MomID
save <original-data>, replace
drop MomID
rename ID MomID
rename Height MomHeight
sort MomID
save <temporary-data-file>
use <original-data>, clear
merge MomID using <temporary-data-file>, nokeep

* You will get a message saying "variable MomID does not uniquely 
identify observations in the master data" because there are multiple 
children of each mother
* nokeep is necessary so that non-mothers records aren't added to the 
file attached to no-one.

assert _merge==1 | _merge==3



> Dear Statlisters,
>
> I would like to match the values of one variable to the values of
> another variable and then create a third variable. Here is the basic setup:
>
> ID      MomID      Height      MomHeight
> 1         .                  5                  .
> 2         1                 6                  5
> 3         .                  6                  .
> 4         1                  5.5               5   ...
>
> MomHeight is the variable I want to create. It seems straightforward,
> but I just can't come up with the right code.
>
> Thank you for any pointers.
Greg
--
***************
Evan Roberts
Minnesota Population Center and Department of History
University of Minnesota
eroberts@pop.umn.edu
http://www.pop.umn.edu/~eroberts
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