这个是我的部分代码:
use temp2, clear
tempfile all_combinations
egen year_province = group(year province)
collapse (first) year_province, by(year province)
save `all_combinations'
use temp2, clear
merge 1:m year province using `all_combinations', nogen
这个是报错:
. merge 1:m year province using `all_combinations', nogen
invalid file specification
谢谢大家,求求了!