Radu Ban
>
> I translated an excel dataset into Stata and now it looks like this
>
> Group1 obs1
> Subgroup1 obs2
> <blank> obs3
> <blank> obs4
> ......... .........
> <blank> obsn1
> Group1 obs1
> Subgroup2 obs2
> <blank> obs3
> ............... ........
> <blank> obsn2
> ............................
> Groupk obs1
> Subgroupl obs2
> <blank> obs3
> .....
> <blank> obsns
>
> I would like to transform this into:
> Group1 Subgroup1 obs1
> Group1 Subgroup1 obs2
> .......... ..................
> Group1 Subgroup2 obs
> Group1 Subgroup2 obs
> ..........
> Group1 Subgroup_n obs
> Group2 Subgroup_n+1 obs
> Group2 Subgroup_n+1 obs
> ..............................
>
>
> I know I could just do the changes in excel by copying and dragging
> but I would like to learn how to do it in Stata.
>
I am going to interpret this as two Stata variables
called -what- and -value-.
First, we pull out the Group identifiers.
One way to select them is that the previous
value of -what- is missing. (This holds for the
very first as well.)
. gen Group = what if missing(what[_n-1])
Very likely this will need to be
a string variable, i.e.
. gen str1 Group = ""
. replace Group = what if missing(what[_n-1])
Now we pull out the Subgroup identifiers.
. gen Subgroup = what if missing(Group)
or as a string variable
. gen str1 Subgroup = ""
. replace Subgroup = what if missing(Group)
Subgroup needs to be copied upwards to the first
line of each Group
. replace Subgroup = Subgroup[_n+1] if !missing(Group)
Now we fill in the blanks in a downwards cascade
. replace Group = Group[_n-1] if missing(Group)
. replace Subgroup = Subgroup[_n-1] if missing(Subgroup)
The reasoning is spelled out at
http://www.stata.com/support/faqs/data/missing.html
I hope that helps.
Nick
[email protected]
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