.- help for ^rprod^ .- . Calculating the row product of observations ------------------------------------------- . ^egen^ newvar ^=^ ^rprod(^varlist^)^ [^if^ exp] [^in^ range] [^, pm^iss^(ignore^|^missing^|^1)^] . . Description ----------- . ^rprod^ provides a multiplicative row function for ^egen^ analogous to the additive ^rsum^ function. The product of observations of meeting optional ^in^ and ^if^ conditions is returned in . ^rprod^ insists that is calculated in double precision. . . Option ------ . ^pm^iss^(ignore|missing|1)^ specifies what is to be the product of a group at least one of whose observations is missing. This is to maintain consistency with another ^egen^ function, ^prod^. . ^pm^iss^(ignore)^, the default, ignores missing values and returns the product of all non-missing values in the group. If all values are missing, then missing is returned. . ^pm^iss^(missing)^ returns missing for the product of observations in a group if any observation in the group is missing. . ^pm^iss^(1)^ returns 1 for the product of observations in a group if all observations in the group are missing. Otherwise it returns the product of all non-missing values. This choice would rarely be made (see Appendix in STB-51 insert for ^_gprod^). . . Examples -------- . ^. list a b c^ a b c 1. 1 1 1 2. 2 3 4 3. 0 1 5 4. 5 0 1 5. 0 0 0 6. . . . 7. 1 . 1 8. 8 3 . 9. 0 . 0 10. . 0 . 11. . . 0 12. . . 6 13. -3 4 5 14. -1 -7 2 15. . . -4 ^. egen k = rprod(a b c )^ (1 missing value generated) ^. list^ a b c k 1. 1 1 1 1 2. 2 3 4 24 3. 0 1 5 0 4. 5 0 1 0 5. 0 0 0 0 6. . . . . 7. 1 . 1 1 8. 8 3 . 24 9. 0 . 0 0 10. . 0 . 0 11. . . 0 0 12. . . 6 6 13. -3 4 5 -60 14. -1 -7 2 14 15. . . -4 -4 ^. egen m = rprod(a b c ), pmiss(missing)^ (8 missing values generated) ^. list^ a b c k m 1. 1 1 1 1 1 2. 2 3 4 24 24 3. 0 1 5 0 0 4. 5 0 1 0 0 5. 0 0 0 0 0 6. . . . . . 7. 1 . 1 1 . 8. 8 3 . 24 . 9. 0 . 0 0 . 10. . 0 . 0 . 11. . . 0 0 . 12. . . 6 6 . 13. -3 4 5 -60 -60 14. -1 -7 2 14 14 15. . . -4 -4 . Author ------ Philip Ryan Department of Public Health University of Adelaide South Australia philip.ryan@@adelaide.edu.au . . Also see -------- . Manual: [R] ^egen^ STB-51: ^_gprod^ On-line: help for ^egen^ ^prod^