help for ^fndmtch2^

Find matching values for one variable in another ------------------------------------------------

^fndmtch2^ var1 var2 [ ^if^ exp ] [ ^in^ range ] [ ^, g^enerate^(^newvar^)^ > ^l^ist ^by(^varlist^) c^ount ^miss^ ]

Description -----------

^fndmtch2^ finds observations for which the value of var1 is matched by (is equal to) some value of var2, whether for the same observation or for some different observation. var1 and var2 should be both numeric or both string.

Options -------

^generate(^newvar^)^ specifies the name of a new variable to hold information on matches. By default, newvar is . if observations are excluded from comparison, 1 if the value of var1 is matched by some value of var2, and 0 otherwise. With the ^count^ option, newvar is . if observations are excluded from comparison, and the number of matches of the value of var1 in var2 otherwise. ^list^ specifies that matching observations should be listed.

At least one of ^generate( )^ and ^list^ should be specified.

^by(^varlist^)^ specifies that matching is to be carried out only within distinct groups defined by byvarlist. Observations with equal values must belong to the same group to count as matching.

^count^ specifies that the number of matches is to be returned.

^miss^ indicates that missing values of var1 should be included in the comparison. By default, they are excluded.

Remarks -------

Consider ^a^ and ^b^ and the results of

^fndmtch2 a b, gen(mtcha)^ ^fndmtch2 b a, gen(mtchb)^ ^a b mtcha mtchb^ 1 5 0 1 2 6 0 0 3 7 0 0 4 8 0 0 5 9 1 0

Examples --------

. ^fndmtch2 a b, list^ . ^fndmtch2 a b, gen(mtcha)^ . ^fndmtch2 a b, gen(mtcha) by(year)^

Author ------

Nicholas J. Cox, University of Durham, U.K. n.j.cox@@durham.ac.uk

Acknowledgments ---------------

This problem was suggested by Brian Uzzi.

See also --------

On-line: @dups@ (if installed), @fndmtch@ (if installed)