st: generate under bylist

[Kit Baum <baum@bc.edu>]

Uma asked

Household     Person     BirthNum        Yr          Desiredcolumn
1                      1              1                      
80                 80
1                      1              2                       
0                   80
1                      1              3                       
0                   80
1                      2               1                      
87                  87
1                      2               2                       
0                   87
2                      1               1                       
90                  90
2                      2                1                      
75                  75
2                      2                 2                         
0                 75
3                       1               1                      
85                  85


Each individual is identified by Household and Person (which is not  
unique). I want to
replace the 0’s in the Yr by the value of Yr when BirthNum=1 for each  
individual. The
last column in the above table shows what I am trying to do. I am  
trying to write a loop in
stata to do the above manipulation. I would appreciate it if you  
could give me guidelines
on how to proceed.


The answer:


     +--------------------+
     | hh   per   bn   yr |
     |--------------------|
  1. |  1     1    1   80 |
  2. |  1     1    2    0 |
  3. |  1     1    3    0 |
  4. |  1     2    1   87 |
  5. |  1     2    2    0 |
     |--------------------|
  6. |  2     1    1   90 |
  7. |  2     2    1   75 |
  8. |  2     2    2    0 |
  9. |  3     1    1   85 |
     +--------------------+

. bysort hh per (bn): replace yr=yr[1]
(4 real changes made)

. l

     +--------------------+
     | hh   per   bn   yr |
     |--------------------|
  1. |  1     1    1   80 |
  2. |  1     1    2   80 |
  3. |  1     1    3   80 |
  4. |  1     2    1   87 |
  5. |  1     2    2   87 |
     |--------------------|
  6. |  2     1    1   90 |
  7. |  2     2    1   75 |
  8. |  2     2    2   75 |
  9. |  3     1    1   85 |
     +--------------------+


You might find some useful advice on the use of bylists in my book,  
URL below.


Kit Baum, Boston College Economics and DIW Berlin
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html


On Jul 5, 2007, at 12:10 PM, Uma Radhakrishnan wrote:


> Hi Kit,
> I am attaching the material in a PDF format.
> Thanks.
> Uma
>
> On Thu, 5 Jul 2007 11:54:49 -0400
>  Kit Baum <baum@bc.edu> wrote:
> > Please do not send me Word documents; I do not use MS Word. If  
> > you  want to send me this material please make it into a PDF,  
> > which you  should be able to do with one click.
> > Thanks
> > Kit
> > Kit Baum, Boston College Economics and DIW Berlin
> > http://ideas.repec.org/e/pba1.html
> > An Introduction to Modern Econometrics Using Stata:
> > http://www.stata-press.com/books/imeus.html
> > On Jul 5, 2007, at 11:15 AM, Uma Radhakrishnan wrote:
> >
> > > Hi Kit,
> > > I have another issue regarding writing a loop over observations  
> > > in  Stata.
> > > I am attaching a word document with the question I have. I  
> > > really  appreciate the help you have previously given me.
> > > Thanks.
> > > Uma
> > > <Stata Help.doc>
> <Stata Help.pdf>

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