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Re: st: extract
Nick Cox <email@example.com>
Re: st: extract
Sat, 19 May 2012 07:19:22 +0100
For "precise" read "precisely".
On Sat, May 19, 2012 at 7:12 AM, Nick Cox <firstname.lastname@example.org> wrote:
> Note that -if- and -in- are not considered to be options. They are
> called qualifiers.
> su X if nvar == 5 & tvar == 1995, meanonly
> local value `r(min)'
> As the -summarize- should select precise one observation, various
> other saved results would work equally well.
> See also
> Nicholas J. Cox. 2011. Speaking Stata: Compared with ...
> Stata Journal 11(2): 305-314
> Abstract. Many problems in data management center on relating values
> to values in other observations, either within a dataset as a whole or
> within groups such as panels. This column reviews some basic Stata
> techniques helpful for such tasks, including the use of subscripts,
> summarize, by:, sum(), cond(), and egen. Several techniques exploit
> the fact that logical expressions yield 1 when true and 0 when false.
> Dividing by zero to yield missings is revealed as a surprisingly
> valuable device.
> On Sat, May 19, 2012 at 3:46 AM, Paulo Regis
> <email@example.com> wrote:
>> I am struggling to extract the value of a variable from a panel.
>> I have a panel where "tvar" is time (eg: 1971-2010, that is data for
>> 40 years ) and "nvar" is the id of each panel (eg: 1,2,... 10, that is
>> data for 10 individuals). My variable of interest is X. I would like
>> to extract the value of X for individual 5 in 1995 and save it in a
>> local. I have tried to use the option "if" but did not work with
>> "local" but did nto work. So far, I managed to use the option "in"
>> with the command "local" but then I have to find the location of X in
>> 1995 for individual 5 by hand.
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