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help cfvars
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Compare variable name lists in two data sets


Syntax

        cfvars filename1 [filename2]


Description

    cfvars compares the lists of variable names in Stata data file filename1
    and

        either Stata data file filename2, if specified,

        or the data currently in memory, otherwise.

    cfvars prints lists of variable names in both datasets (if any) and in
    each dataset but not the other (again, if any in either case).


Remarks 

    Note that filenames must be those of Stata .dta files and must be
    enclosed in double quotes whenever they include spaces.  The .dta
    extension is not required and will be added if absent.

    Note also that there is absolutely no checking of variable values.  That
    is the job of cf.


Examples

    . sysuse auto
    . drop mpg
    . cfvars auto.dta

    . cfvars frog.dta toad.dta
    . cfvars frog toad

    . cfvars "c:\somewhere\older frog.dta" frog.dta


Saved results 

    r(both)      list of variable names in both
    r(oneonly)   list of variable names only in first-named file
    r(twoonly)   list of variable names only in second-named file or data in
    memory
    r(same)      1 if datasets have same variable names, 0 otherwise

    Note that r(same) is always returned. The other results are returned only
    if not empty. Even if not returned, a subsequent test such as "`r(both)'"
    == "" will return 1 (true) as usual.


Author 

    Nicholas J. Cox, Durham University, UK
    n.j.cox@durham.ac.uk


Acknowledgments 

    This problem was suggested on Statalist by David Kantor on 19 February
    2009. Several people contributed ideas to the resulting thread.


Also see

    help for cf, describe, ds, unab