by var1 (var2) by var1 var2 stata

是 否 +2 论坛币

k人 参与回答

经管之家送您一份

应届毕业生专属福利!

求职就业群

赵安豆老师微信：zhaoandou666

经管之家联合CDA

送您一个全额奖学金名额~ !

立即领取

感谢您参与论坛问题回答

经管之家送您两个论坛币！

+2 论坛币

The varlist1 (varlist2) syntax is of special use to programmers.  It verifies that the data are sorted by
    varlist1 varlist2 and then performs a by as if only varlist1 were specified.  For instance,

        by pid (time): generate growth = (bp - bp[_n-1])/bp

    performs the generate by values of pid but first verifies that the data are sorted by pid and time within pid.


在论坛见到很多次by varlist1 (varlist2) 和 by varlist1 varlist2，之前有混用过，今天查了下帮助文件，发现应该是有区别的，括号的意思是，括号里的变量参与排序但不作为分组变量参与计算。例子如上。

另外，
by和bys的区别在于前者没有排序，要求数据是已经排好序的，后者命令可以排序。

Syntax

        by varlist: stata_cmd

        bysort varlist: stata_cmd

    The above diagrams show by and bysort as they are typically used.  The full syntax of the commands is

        by varlist1 [(varlist2)] [, sort rc0]:  stata_cmd

        bysort varlist1 [(varlist2)] [, rc0]:  stata_cmd

例如by rep78, sort:  tabulate foreign等价于bysort rep78: tabulate foreign

扫码加我 拉你入群

请注明：姓名-公司-职位

以便审核进群资格，未注明则拒绝

分享0 收藏0 回帖

关键词：Stata tata VaR Programmers Programmer