mf_st_tsrevar.hlp

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{smcl}
{* 23mar2005}{...}
{cmd:help mata st_tsrevar()}
{hline}
{* index stata time-series operated variable}{...}
{* index st_tsrevar()}{...}

{title:Title}

{p 4 4 2}
{bf:[M-5] st_tsrevar() -- Create time-series op.varname variables}


{title:Syntax}

{p 8 12 2}
{it:real rowvector}
{cmd:st_tsrevar(}{it:string rowvector s}{cmd:)}


{title:Description}

{p 4 4 2}
{cmd:st_tsrevar(}{it:s}{cmd:)} is the equivalent of Stata's 
{bf:{help tsrevar:[TS] tsrevar}} programming command:  It generates temporary 
variables containing the evaluation of any {it:op}{cmd:.}{it:varname}
combinations appearing in {it:s}.


{title:Remarks}

{p 4 4 2}
In {it:s} you have a rowvector of
Stata variable names, some of which might contain 
time-series {it:op}{cmd:.}{it:varname} combinations (such as {cmd:l.gnp}).
Say {it:s} contains

	{it:s} = {cmd:("gnp", "r", "l.gnp")}

{p 4 4 2}
You want to create a view of the data in {it:V}, but you cannot code 

	{cmd:st_view(}{it:V}{cmd:, .,} {it:s}{cmd:)}

{p 4 4 2}
because {bf:{help mf_st_view:[M-5] st_view()}} does not allow time-series
operated variables.  The solution is to code

	{cmd:st_view(}{it:V}{cmd:, ., st_tsrevar(}{it:s}{cmd:))}

{p 4 4 2}
{cmd:st_tsrevar()} will create temporary variables for each 
{it:op}{cmd:.}{it:varname}
combination ({cmd:l.gnp} in our example), and then return the 
Stata variable indices of each of the variables, whether newly created 
or already existing.  For instance, in the example above, let us assume 
that {cmd:gnp} is the 2nd variable in the dataset, {cmd:r} the 23rd, and that,
in total, there are 54 variables.  Returned by {cmd:st_tsrevar()} will be (2,
23, 55).  Variable 55 is new, created by {cmd:st_tsrevar()}, and it
contains the values of {cmd:l.gnp}.


{title:Conformability}

    {cmd:st_tsrevar(}{it:s}{cmd:)}:
		{it:s}:  1 {it:x c}
	   {it:result}:  1 {it:x c}


{title:Diagnostics}

{p 4 4 2}
{cmd:st_tsrevar()} aborts with error if any variable name is not found
or any {it:op}{cmd:.}{it:varname} combination is invalid.


{title:Source code}

{p 4 4 2}
Function is built-in.


{title:Also see}

{p 4 13 2}
Manual:  {hi:[M-5] st_tsrevar()}

{p 4 13 2}
Online:  help for 
{bf:{help mf_st_varname:[M-5] st_varname()}};
{bf:{help m4_stata:[M-4] stata}}
{p_end}