原始数据
stkcd | year | variable |
1 | 1999 | 1 |
1 | 2004 | 2 |
1 | 2007 | 2 |
1 | 2009 | 6 |
1 | 2011 | 1 |
2 | 2003 | 1 |
2 | 2007 | 2 |
2 | 2011 | 3 |
3 | 2003 | 1 |
4 | 2002 | 2 |
4 | 2003 | 1 |
4 | 2004 | 1 |
4 | 2005 | 1 |
4 | 2007 | 3 |
4 | 2008 | 1 |
4 | 2009 | 1 |
4 | 2010 | 1 |
4 | 2011 | 1 |
4 | 2012 | 9 |
4 | 2013 | 1 |
4 | 2014 | 5 |
5 | 2014 | 1 |
目标的样式:
stkcd | year | variable |
1 | 1999 | 1 |
1 | 2000 | |
1 | 2001 | |
1 | 2002 | |
1 | 2003 | |
1 | 2004 | 2 |
1 | 2005 | |
1 | 2006 | |
1 | 2007 | 2 |
1 | 2008 | |
1 | 2009 | 6 |
1 | 2010 | |
1 | 2011 | 1 |
1 | 2012 | |
1 | 2013 | |
1 | 2014 | |
1 | 2015 |