True, but "creat a unique number to identify each set from a-b" does
not uniquely identify the method of assigning an index variable when
"b" may occur serially. My method assumes every instance of "b"
increments the index. Even better might be
. gen long var2=1+sum(var1[_n-1]=="b") if !(var1[_n-1]=="b" & var1=="b")
to give, e.g.
var1 index var2
a 1 1
a 1 1
a 1 1
b 1 1
a 2 2
a 2 2
a 2 2
b 2 2
a 3 3
a 3 3
a 3 3
b 3 3
b 4 .
a 5 4
a 5 4
a 5 4
b 5 4
a 6 5
a 6 5
forcing the user to make a separate choice about repeated "b" cases, such as
. replace var2= var2[_n-1] if mi(var2)
On 8/26/05, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> This assumes, I think, that "b" occurs only
> as singletons, true of the example Kelly
> gave but otherwise not explicit.
>
> Nick
> n.j.cox@durham.ac.uk
>
> austin nichols
>
> > gen long index=1+sum(var1[_n-1]=="b")
> >
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