Re: st: how to access Stata's record of the variable data is sorted on

[Nick Cox <njcoxstata@gmail.com>]

It's not a local macro. If it were a local macro, it could be not
visible everywhere. It's an extended macro function.

The use of the `: ' syntax to evaluate it is to be thought of as
similar to, but certainly not identical.

For some technique, consider

. sysuse auto, clear
(1978 Automobile Data)

. di "`: sortedby'"
foreign

. mata :
------------------------------------------------- mata (type end to
exit) --------------
: which = "foreign"

: which == sprintf("`: sortedby'")
  1

: end

Nick
njcoxstata@gmail.com


On 24 September 2013 19:12, László Sándor <sandorl@gmail.com> wrote:
> Thanks!
>
> I cannot get it working in Mata though. st_local(":sorted by") returns
> an empty string, while the local is accessed fine in Stata. What is
> the way around this? (And why does this happen, by the way?)
>
> On Mon, Sep 23, 2013 at 1:24 PM, Robert Picard <picard@netbox.com> wrote:
>> dis "`:sortedby'"
>>
>> On Mon, Sep 23, 2013 at 12:52 PM, László Sándor <sandorl@gmail.com> wrote:
>>> Hi,
>>> [D] sort documents how Stata keeps track of the variable the data has
>>> been sorted on, and you see this information as the last line of the
>>> output from -describe-. However, I cannot find a way to access this
>>> information and make use of it. Is there any?
>>>
>>> For those interested, I think I have a legitimate use case when I want
>>> to use this. Sorting my data can take a long-long time, even if the
>>> variable is categorical. But as I need a -tab- of the categories
>>> anyway, I can utilize the frequencies returned to assign a rank for a
>>> new sort order for -mf_collate-. This should be much faster. But I
>>> would be happy to skip this step completely if the data is already
>>> sorted on the variable when my command is invoked.

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