Find non-unique values or observations --------------------------------------
^finddup^ varlist [^if^ exp]^,^ [^nom^iss ^nol^ist ^k^eep]
^finddup^ identifies values or observations which are not unique, and lists each such value or observation together with the rank order in which it occurs. Optionally, this information can be added to the data set using the ^keep^ option. ^finddup^ display all duplicates, but by the use of the ^nomiss^ option, observations with missing values can be excluded from the analysis.
Options -------
^nomiss^ requests that values or observations with missing values not be analyzed.
^nolist^ requests that results not be displayed. This may be useful when used with the keep option and a current display of duplicates is not required.
^keep^ requests that a new variable, dupval, be added to the data set.
Note ----
Non-unique observations can be identified by -finddup _all. Non-unique values are identified by using less than the full varlist.
Examples -------- . l id encountr othervar 1. 1 1 1 2. 1 1 7 3. 1 2 5 4. 2 1 3 5. 2 2 3 6. 3 1 3 7. 3 1 4 8. 3 2 27 9. 3 2 . 10. . . . 11. . . 1 12. . . . . finddup id encountr id encountr dupval 1. 1 1 1 2. 1 1 2 6. 3 1 1 7. 3 1 2 8. 3 2 1 9. 3 2 2 10. . . 1 11. . . 2 12. . . 3 . finddup id encountr, nom k id encountr dupval 1. 1 1 1 2. 1 1 2 6. 3 1 1 7. 3 1 2 8. 3 2 1 9. 3 2 2
Author ------
Fred Wolfe, Arthritis Research Center fwolfe@@southwind.net, 26 July 1997
Also see --------
chkdup in STB reprints Vol 1, page 30.