1、用list make weight 显示数据
3、用replace命令replace weight=weight/1000
5、list中nolabel参数的使用。list make foreign price predprice,nobel步骤4中foreign 显示为domestic和foreign，而步骤5中foreign 显示为0和1
7、显示自定义变量.list make foreign where
9、定义model变量和modelwhere变量 gen model =usubstr(make,ustrpos(make,"")+1,.) gen modelwhere =model +" " + where
