st: sum up many variables with missing values across columns

[daniel klein <klein.daniel.81@googlemail.com>]

Daifeng,

I think there are many ways of doing this. One is to use -egen-s
-rowmiss- function like in

. egen hasmiss = rowmiss(var1-var100)
. egen sumup = rowtotal(var1-var100)
. replace sumup = . if hasmiss

I have an ado-file, -chm- (available from SSC), that can also be used
for this. You would have to type

. chm var1-var100 ,soft : egen sumup = rowtotal(var1-var100)

or, if you have already (e)generated the new variable

. chm var1-var100 sumup ,replace soft

Best
Daniel

---
Hi there,

I am trying to sum up say 100 variables across columns, but many of
the 100 variables have missing values. And I want the sum to be
missing if any of the 100 variables is missing.   -rowtotal- does not
work because it treats missing values as 0; even with the option -,
missing-, it generates a missing value only when all the 100 variables
are missing.

Does anybody know how to do this efficiently instead of typing varx+
vary+ var z+... varxx+varyy+varzz?  My variables do not have a common
stub in the variable names so I cannot use a loop.
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/