你若要问程序，永远附上相关资料；若附上资料，永远用 dataex 印出资料。
1.        先 ssc install dataex (并见说明)，将原始 Stata 资料中具有”代表性”的一部分资料列出，以供有意回答者实验之用，并能提供具体操作指令。
2.        并请参考 http://www.jianshu.com/p/9870080fe769,  https://bbs.pinggu.org/thread-5048204-1-1.html, 与 https://bbs.pinggu.org/thread-5917273-1-1.html。
3.        你若要别人帮助你，你就要"动点脑筋"帮助别人来帮助你。

谢谢楼上的

. dataex year cic in 1/100

----------------------- copy starting from the next line -----------------------
[CODE]
* Example generated by -dataex-. To install: ssc install dataex
clear
input int year str4 cic
2012 "2440"
2007 "3625"
2008 "3625"
2006 "3010"
2010 "1810"
2008 "0610"
2004 "1810"
2005 "1810"
2007 "1810"
2010 "1810"
2009 "4412"
2010 "4420"
2010 "2190"
2010 "1762"
1998 "4317"
1999 "4317"
2000 "4317"
2001 "4317"
2002 "4317"
2013 "3391"
2004 "1019"
2005 "1019"
2006 "1019"
2007 "1019"
2003 "3921"
2004 "3725"
2005 "3921"
2007 "3921"
2001 "1723"
1998 "3450"
1999 "3450"
2000 "3450"
2001 "3450"
2002 "3450"
2003 "3440"
2004 "3440"
2005 "3440"
2006 "3440"
1998 "1721"
1999 "1772"
2000 "1772"
2001 "1772"
2002 "1772"
2003 "1759"
2004 "1759"
2003 "2664"
2004 "2664"
2005 "2664"
2006 "2664"
2007 "2664"
2009 "1011"
2004 "2319"
2005 "2319"
2007 "2022"
2001 "3485"
2002 "3485"
2003 "3451"
2004 "3451"
2005 "3451"
2006 "3451"
2007 "3451"
2004 "0610"
2005 "0610"
2007 "2520"
2006 "3651"
2008 "3651"
2007 "3230"
2007 "1810"
2008 "1810"
2006 "3724"
1998 "1031"
1999 "1031"
2000 "1031"
2001 "1031"
2002 "1031"
2003 "1030"
2004 "1030"
2005 "1030"
2007 "1030"
2008 "1320"
2009 "4153"
2007 "2110"
2008 "1012"
2009 "1012"
1998 "1390"
1999 "1390"
2000 "1390"
2006 "3412"
2007 "3412"
2008 "3412"
2010 "3412"
2006 "2231"
2003 "2319"
2004 "2319"
2005 "2312"
2007 "2312"
1998 "2619"
1999 "2619"
2000 "2619"
2001 "2619"
end

将cic前两位相同的样本挑出来，如何操作？

1. 尔后请用回复。2. 试试3. 什么叫做"将cic前两位相同的样本挑出来"？