我有两个data.tables。如果dfB
中的dfA
对应于year
中的dfA
一年之前,则我想将第二个data.table year
的行与第一个dfB
合并。
作为示例,dfB
的第一行将与dfA
的第一行合并,因为dfB
的年份为2009,比dfA
的年份为2010。
library(data.table) dfA <- fread(" A B C D E F G Z iso year matchcode 1 0 1 1 1 0 1 0 NLD 2010 NLD2010 2 1 0 0 0 1 0 1 NLD 2014 NLD2014 3 0 0 0 1 1 0 0 AUS 2010 AUS2010 4 1 0 1 0 0 1 0 AUS 2006 AUS2006 5 0 1 0 1 0 1 1 USA 2008 USA2008 6 0 0 1 0 0 0 1 USA 2010 USA2010 7 0 1 0 1 0 0 0 USA 2012 USA2012 8 1 0 1 0 0 1 0 BLG 2008 BLG2008 9 0 1 0 1 1 0 1 BEL 2008 BEL2008 10 1 0 1 0 0 1 0 BEL 2010 BEL2010 11 0 1 1 1 0 1 0 NLD 2010 NLD2010 12 1 0 0 0 1 0 1 NLD 2014 NLD2014 13 0 0 0 1 1 0 0 AUS 2010 AUS2010 14 1 0 1 0 0 1 0 AUS 2006 AUS2006 15 0 1 0 1 0 1 1 USA 2008 USA2008 16 0 0 1 0 0 0 1 USA 2010 USA2010 17 0 1 0 1 0 0 0 USA 2012 USA2012 18 1 0 1 0 0 1 0 BLG 2008 BLG2008 19 0 1 0 1 1 0 1 BEL 2008 BEL2008 20 1 0 1 0 0 1 0 BEL 2010 BEL2010", header = TRUE) dfB <- fread(" A B C D H I J K iso year matchcode 1 0 1 1 1 0 1 0 NLD 2009 NLD2009 2 1 0 0 0 1 0 1 NLD 2014 NLD2014 3 0 0 0 1 1 0 0 AUS 2011 AUS2011 4 1 0 1 0 0 1 0 AUS 2007 AUS2007 5 0 1 0 1 0 1 1 USA 2007 USA2007 6 0 0 1 0 0 0 1 USA 2010 USA2010 7 0 1 0 1 0 0 0 USA 2013 USA2013 8 1 0 1 0 0 1 0 BLG 2007 BLG2007 9 0 1 0 1 1 0 1 BEL 2009 BEL2009 10 1 0 1 0 0 1 0 BEL 2012 BEL2012", header = TRUE)
我想尝试:
dfA <- merge(dfA , dfB, on =.(iso, year == year-1), all.x = TRUE, allow.cartesian=FALSE)
但是那会在年份上产生匹配,这不是我想要的。
我相信
roll
也会尝试找到最接近的匹配项。
我应该如何编写此合并?
我有两个data.tables。如果来自dfA的年份对应于dfB中的前一年,我想将第二个data.table dfB的行与第一个dfA合并。例如,dfB ...
有点杂乱,但是尝试:
dfB[dfA[,c(.SD,.(year1=year-1))],
on=.(A,B,C,D,iso,year == year1)]
A B C D H I J K iso year matchcode E F G Z i.year i.matchcode
1: 1 0 1 1 1 0 1 0 NLD 2009 NLD2009 1 0 1 0 2010 NLD2010
2: 2 1 0 0 NA NA NA NA NLD 2013 <NA> 0 1 0 1 2014 NLD2014
3: 3 0 0 0 NA NA NA NA AUS 2009 <NA> 1 1 0 0 2010 AUS2010
4: 4 1 0 1 NA NA NA NA AUS 2005 <NA> 0 0 1 0 2006 AUS2006
5: 5 0 1 0 1 0 1 1 USA 2007 USA2007 1 0 1 1 2008 USA2008
6: 6 0 0 1 NA NA NA NA USA 2009 <NA> 0 0 0 1 2010 USA2010
7: 7 0 1 0 NA NA NA NA USA 2011 <NA> 1 0 0 0 2012 USA2012
8: 8 1 0 1 0 0 1 0 BLG 2007 BLG2007 0 0 1 0 2008 BLG2008
9: 9 0 1 0 NA NA NA NA BEL 2007 <NA> 1 1 0 1 2008 BEL2008
10: 10 1 0 1 NA NA NA NA BEL 2009 <NA> 0 0 1 0 2010 BEL2010
11: 11 0 1 1 NA NA NA NA NLD 2009 <NA> 1 0 1 0 2010 NLD2010
12: 12 1 0 0 NA NA NA NA NLD 2013 <NA> 0 1 0 1 2014 NLD2014
13: 13 0 0 0 NA NA NA NA AUS 2009 <NA> 1 1 0 0 2010 AUS2010
14: 14 1 0 1 NA NA NA NA AUS 2005 <NA> 0 0 1 0 2006 AUS2006
15: 15 0 1 0 NA NA NA NA USA 2007 <NA> 1 0 1 1 2008 USA2008
16: 16 0 0 1 NA NA NA NA USA 2009 <NA> 0 0 0 1 2010 USA2010
17: 17 0 1 0 NA NA NA NA USA 2011 <NA> 1 0 0 0 2012 USA2012
18: 18 1 0 1 NA NA NA NA BLG 2007 <NA> 0 0 1 0 2008 BLG2008
19: 19 0 1 0 NA NA NA NA BEL 2007 <NA> 1 1 0 1 2008 BEL2008
20: 20 1 0 1 NA NA NA NA BEL 2009 <NA> 0 0 1 0 2010 BEL2010