qiangli 发表于 2015-8-26 08:36 
> rm(list=ls())
> data
>
多谢!我已经用上面的coding做出表格,还想请教一个问题,如果我原本的栏位有多一栏,像这样:
ID Year data locate
A3405533 2014 29 A
A3405533 2014 17 A
A3405533 2013 23.6 A
A3500131 2014 7.4 B
A3600190 2014 12.5 C
A3600190 2014 5.4 C
A3600190 2013 21.3 C
A3600190 2013 8 C
A3600190 2013 3.7 C
A3600190 2013 11.6 C
A3600190 2012 14.05 C
A3600190 2012 10.5 C
A3701656 2014 20.2 D
A3701656 2013 4.3 D
要做出这样:
ID Year data locate
A3405533 2014 46 A
A3405533 2013 23.6 A
A3500131 2014 7.4 B
A3600190 2014 17.9 C
A3600190 2013 44.6 C
A3600190 2012 24.55 C
A3701656 2014 20.2 C
A3701656 2013 4.3 D
我用这个指令是否正确?因为locate只是我仍然想要放入的资讯,并不是要整合计算的标准,如果放在+后面,会不会有计算错误的情形?