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RE: st: Reshape like problem


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Reshape like problem
Date   Fri, 5 Jun 2009 12:53:34 +0100

This isn't a reshape-like problem in my book, as no overall change to data structure or shape is needed: you just want new identifier variables. 

In the example -id- was just equivalent to observation number. In that circumstance

gen ID_1 = ceil(_n/3) 

is an alternative, as are 

egen id__1 = seq(), block(3)
egen id__2 = seq(), to(3) 

The first is easy to think about: you are just rounding up 1/3, 2/3, 3/3, 4/3, ... to the next integer. 

The second two are just wrappers for trickery with -mod()- and -int()-. (I think -egen, seq()- predates -ceil()-.) 

Nick 
n.j.cox@durham.ac.uk 

Austin Nichols

Pancho Villa <panchovillainnyc@gmail.com> :

clear
input id value
1 15
2 14
3 22
4 31
5 12
6 10
end
g id_1=(id-mod(id-1,3)-1)/3+1
g id_2=mod(id-1,3)+1
l


On Thu, Jun 4, 2009 at 2:15 PM, Pancho Villa <panchovillainnyc@gmail.com> wrote:

> I have my data in this kind of form:
>
> id      value
> 1       15
> 2       14
> 3       22
> 4       31
> 5       12
> 6       10
>
> id_1    id_2    value
> 1       1       15
> 1       2       14
> 1       3       22
> 2       1       31
> 2       2       12
> 2       3       10
>
> In other words, my data is stacked and would like to un-stack it.  (I
> can do reshape, I think.  But this seems like a necessary first step.)
>
> Now, in my example, my id goes from 1 to 6, while I'd like id_1 to go
> from 1 to 2 and id_2 from 1 to 3.   In reality, my id goes from 1 to
> 5084280, while I want id_1 to go from 1 to 2088 and id_2 from 1 to
> 2435.  (If you check, 2088 x 2435 = 5084280.)
>
> I'll really appreciate if you can share code addressing a very similar
> problem so I can just paste it in my do file and tweak a few things.

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