Looks like
by hhid : gen mage = age[mlineno]
to me. No loops, no -merge-.
Nick
[email protected]
Friedrich Huebler
> I appreciate the responses that I received so far but realize that my
> initial message was not precise enough.
>
> The variable mlineno lists the line number of a household member's
> mother. In household 1 in my example data, household member 2 is the
> mother of household member 3. In household 2, 1 is the mother of 2,
> and 3 is the mother of 4 and 5. I would like to create a variable
> that lists the age of each household member's mother. The result
> should look like this:
>
> hhid lineno age mlineno mage
> 1 1 32 . .
> 1 2 30 . .
> 1 3 5 2 30
> 2 1 68 . .
> 2 2 41 1 68
> 2 3 40 . .
> 2 4 17 3 40
> 2 5 14 3 40
>
> The loop that I am using to create the variable mage works perfectly
> but it is very slow with a large number of observations.
>
> Friedrich
>
> --- Friedrich Huebler <[email protected]> wrote:
> > I am looking for advice to speed up a loop. The loop determines
> > characteristics of other household members in household survey data
> > and is taken from this Stata FAQ:
> >
> > http://www.stata.com/support/faqs/data/members.html
> >
> > The data has the variables hhid (household ID), lineno (line number
> > of household member), age, and mlineno (mother's line number).
> >
> > hhid lineno age mlineno
> > 1 1 32 .
> > 1 2 30 .
> > 1 3 5 2
> > 2 1 68 .
> > 2 2 41 1
> > 2 3 40 .
> > 2 4 17 3
> > 2 5 14 3
> >
> > The following code creates the variable mage with the mother's age.
> >
> > gen byte mage=.
> > sum lineno, meanonly
> > forvalues i = 1/`r(max)' {
> > gen byte tag = 1 if lineno==`i'
> > bysort hhid: egen byte iage = max(tag*age)
> > replace mage=iage if mlineno==`i'
> > drop tag iage
> > }
> >
> > I tried changing -bysort hhid- to -by hhid- but the time needed for
> > the loop is the same. Running the loop -quietly- also makes no
> > difference. Can anything be done to make this loop go faster?
> >
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