黃河泉 发表于 2018-5-19 10:32 
你若要问程序,永远附上资料;若要附上资料,永远用 dataex 印出资料;先 ssc install dataex (并见说明), ...
谢谢老师指点,
数据形式如下
----------------------- copy starting from the next line -----------------------
------------------ copy up to and including the previous line ------------------
Listed 14 out of 14 observations