st: Looping across variables in variable columns

["Mungai, Edward" <DOCEMungai@iese.edu>]

Thanks for the answer. We illustrate the problem with a short example.

 

We aim to test that parents economic performance being good, denoted  (1) or bad, denoted (0) when children are ages 16 years and 17years may influence the children career behaviour even much later in life.

 

We have the information on the parental economic perfomance for a period of years, 1970 to 1972 in this example. We also know the years when the children were 16yrs and 17yrs which may, may-not or only partially overlap with the years of parental economic perfomance which we have available.

For years when the parental influence is not available, we assume the influence was bad i.e. value zero in the example.

 

The problem is to get a stata loop to compute the total parental influence for each child. 

In the example,  this total would be 2 for Mark, 1 for Paul and 0 for John.  

 

Child 	Par. Inf.1970	 Par. Inf.1971	 Par.Inf. 1972	     Yr. 16yrs	     Yr.17yrs	   Total par.Inf.	
Mark	 1	 1	 1	 1970	 1971 	       ?	
Paul	 0	 1	 0	 1971	 1972	       ?	
John	 1	 1	 0	 1972	 1973	        ?   	


________________________________

From: owner-statalist@hsphsun2.harvard.edu on behalf of Maarten Buis
Sent: Thu 26/04/2007 10:39
To: statalist@hsphsun2.harvard.edu
Subject: st: RE: Looping across variables in variable columns 



Somehow there should be information in your dataset about which columns should be added. Ways of solving this problem depends on how that information is stored, and as you didn't tell us, there is not much we can do to help you. So how do you know which columns to add?

-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Mungai, Edward
Sent: donderdag 26 april 2007 4:28
To: statalist@hsphsun2.harvard.edu
Subject: st: Looping across variables in variable columns

I have seen discussions on looping across an unknown number of columns which can be solved by -reshape-

My question is how to sum across columns where the number of columns varies from one observation to the next.  i.e. I may need to sum columns 2 to 5 for the first observation but from columns 4 to  11 for the second observation. In all cases the summation is done across a set of  adjacent columns.

I have tried to use -rowcount-,  and the looping functions but as far as I can tell all sum across a fixed number of columns from one observation to the next. But there is something good also; the information on the column to  begin and the column to end the summation for each observation is contained  in two adjacent column which are the same for all the observations.

Feedback is highly appreciated upfront.

Edward.


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