gen month= real(substr(time,6,2))
gen yearm=ym(year, month)
format yearm %tm
generate y=sum(foreignassets)
drop var21 month var21 month time
move yearm foreignassets
tsset yearm //repeated time values in sample 定义时间序列
duplicates report
duplicates e yearm
duplicates drop yearm,force
*******************
generate y=sum(foreignassets) // 累加
egen y2=sum(foreignassets) // 全部加总
egen y2=sum(foreignassets),by(year) // 组内汇总按年度
但是我跑的时候经常发现sdecode unrecognized,然后把sdecode去掉以后时间序列又做不出来,求大家帮忙看看代码在哪里出错!谢谢啦!