----------------- help for sumsum -----------------Compute sums of variables -------------------------

Syntax ------

sumsum varlist [, detail varnames ]

The sumsum command is used to compute sums of variables, and to compute sums of the sums. This is a very useful command for double checking data transformations. The varlist is required, and can contain abbreviations including _all wildcards, e.g. test* - , e.g. inc80-inc90

Options -------

detail - By default, sumsum will compute sums of all of the variables in varlist, and then sum all of those sums, and report the grand sum. You can specify the detail option to obtain the sums for each of the individual variables. varnames - When using wildcards or - in the varlist, it is possible that the varlist may include (or exclude) variable you thought to be in the list. If you dont use the detail option, you can use the varnames option to double check that the variable list (after expansion of the wildcards) contain the variables you expected it to contain.

A Note about the - with varlists ----------------------------------

You might expect x1-x3 to always return x1 x2 x3, however the - really focuses on the position of the variables in the data file, not the names of the variables in the data file. So if you have x and y that alternate like x1 y2 x2 y2 x3 y3, then x1-x3 will return x1 y1 x2 y2 x3 . If you use neither the detail nor varnames option, you might believe that the sum of x1 x2 x3 is really the sum of x1 y1 x2 y2 x3.

You can use the aorder command to change the position of the variables in your data file to be in alphabetic order. Then, after using aorder, the varlist x1-x3 will refer to x1 x2 x3.

Author ------

Michael N. Mitchell Statistical Computing and Consulting UCLA, Office of Academic Computing mnmatucla.edu