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Re: st: AW: compare files, vars only


From   Austin Nichols <[email protected]>
To   [email protected]
Subject   Re: st: AW: compare files, vars only
Date   Thu, 19 Feb 2009 11:39:52 -0500

All--
Loading the whole dataset may hog memory, but
 use in 1 using...
works fine, as shown in my previous post.  -describe- would be
preferable, since it does not load the data in memory at all, but it
does not save a list of variables, and _describe is built-in, hence
not hackable.  It would be possible to write a program that loads no
data and gets all the variable lists, either by parsing the output of
_describe using -file- commands, or as is Sergiy's wont, via a direct
file-access approach.  But it wouldn't be nice if there were a Mata
command to get a view onto a dataset not in memory?

On Thu, Feb 19, 2009 at 11:24 AM, Johannes Geyer <[email protected]> wrote:
> what about:
>
>  *************
>  clear*
>  sysuse auto, clear
>  drop  gear_ratio displacement
>  save newauto, replace
>  sysuse auto, clear
>  qui ds
>  loc first `r(varlist)'
>
>  des using auto, varlist
>
>  loc second `r(varlist)'
>  loc diff: list first - second
>  di in red "Differences: `diff'"
>  *************
>
> -describe- does not need to load the dataset which may be of interest here
>
>
> Johannes
>
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