On Saturday, August 2, 2003, at 02:33 AM, Dimitriy wrote:
sum group
scalar min=r(min)
scalar max=r(max)
local i=min
while `i'<=max {
display _newline(2) "group is `i'"
tab race if group==`i'
tab sex if group==`i'
tab race sex if group==`i'
local i=`i'+1
}
Scalar min and max are defined as the min and max of your group
variable.
In your case, min is 1 and max is 50. You could have specified them
yourself instead of defining a scalar. The loop goes trough your group
variable and executes commands based for each group i.
This is better done with forvalues, as Fred Wolfe suggested.
Unfortunately forvalues does not appear in the base Stata
documentation, but it is well documented on-line and in FAQs. But this
approach will fail as soon as one of the groups is missing (what if no
one is in group 37)? In that case foreach, most handily driven by the
new levels command, is the way to go. Although levels, originally
written by Nick Cox, is now an (undocumented) component of Stata 8, it
may be used by Stata 7 users with 'ssc install levels', which will
provide levels7, with most of the same functionality.
Kit
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