James Harris posted this code.
foreach ICD in i21 {
foreach age in 25 35 45 {
foreach sex in m f {
local deaths = "`ICD'_`age'`sex'"
local population = "pop`age'`sex'"
macro list
list year `ICD'_`age'`sex' pop`age'`sex' `deaths' `population'
poisson `deaths' year, exposure (`population')
}
}
}
Phil Ryan answered the associated question. I just want
to comment on one detail.
In the macro assignment
local deaths = "`ICD'_`age'`sex'"
what you're doing is just asking Stata to insert strings
in appropriate places; there is no use of string
functions or operators. In such cases the = sign
is not necessary and you can just go
local deaths "`ICD'_`age'`sex'"
Going further: there is a positive benefit
to doing this when you are dealing with very
long strings. It is not pertinent here, as the
string concerned is a variable name, but there
is a limit to string expression lengths which can be handled
(it varies: see help on -limits-). In other problems
this can lead to bizarre bugs when long strings are
truncated.
In short,
local deaths = "`ICD'_`age'`sex'"
local deaths "`ICD'_`age'`sex'"
are not exactly equivalent. It is a better habit
to use the second form. (As said, this hinges
on not using here any string operators or functions.)
Nick
[email protected]
<<winmail.dat>>
