用preserve和restore来复原数据

[视频作者] 八戒聊基金

[视频时长] 1:41

[视频类型] 财经商业

********preserve***restore***** clear sysuse auto keep if price>4000 clear sysuse auto preserve keep if price>4000 restore *****一起运行 clear sysuse auto preserve keep if price>4000 drop price drop mpg restore