{smcl}
{* 20sep2005}{...}
{hline}
help for {hi:isvar}
{hline}

{title:Filter names into variable names and others}

{p 8 17 2}
{cmdab:isvar} {it:possiblevarlist}


{title:Description}

{p 4 4 2}
{cmd:isvar} takes a list of names that might name variables in
your dataset and filters it into a list of those names that are indeed 
variable names and a list of the others. 

{p 4 4 2} 
One application of {cmd:isvar} arises when you are moving between similar
datasets, especially if they are large, but are not sure which variables are
defined in which dataset. Commands such as {help describe} would fail at the
first name not in fact a variable name. {cmd:isvar} offers a more direct way to
establish existence or non-existence of several possible variables. 


{title:Saved results} 

{p 4 8 2}r(varlist)   names of variables in current dataset{p_end}
{p 4 8 2}r(badlist)   names that do not correspond to variables in current dataset 


{title:Examples}

{p 4 8 2}{cmd:. isvar mpg rep78 rep77}{p_end}
{p 4 8 2}{cmd:. local OKlist "`r(varlist)'"}{p_end}
{p 4 8 2}{cmd:. su `OKlist'} 


{title:Author}

{p 4 4 2}Nicholas J. Cox, Durham University, U.K.{break} 
         n.j.cox@durham.ac.uk


{title:Acknowledgements} 

{p 4 4 2}This problem was suggested by Amadou Diallo. 


{title:Also see}

{p 4 13 2}
Online:  help for {help describe}; {help unab} 

