Question

我有2个非常大的数据集，如下所示：

merge_data <- data.frame(ID = c(1,2,3,4,5,6,7,8,9,10), 
                         position=c("yes","no","yes","no","yes", 
                                    "no","yes","no","yes","yes"),
                         school = c("a","b","a","a","c","b","c","d","d","e"),
                         year1 = c(2000,2000,2000,2001,2001,2000,
                                   2003,2005,2008,2009), 
                         year2=year1-1)


 merge_data

 ID position school year1 year2
 1   1  support   a  2000  1999
 2   2   oppose   b  2000  1999
 3   3  support   a  2000  1999
 4   4   oppose   a  2001  2000
 5   5  support   c  2001  2000
 6   6   oppose   b  2000  1999
 7   7  support   c  2003  2002
 8   8   oppose   d  2005  2004
 9   9  support   d  2008  2007
 10 10  support   e  2009  2008



merge_data_2 <- data.frame(year=c(1999,1999,2000,2000,2000,2001,2003
                                  ,2012,2009,2009,2008,2002,2009,2005,
                                  2001,2000,2002,2000,2008,2005),
                           amount=c(100,200,300,400,500,600,700,800,900,
                                    1000,1100,1200,1300,1400,1500,1600,
                                    1700,1800,1900,2000), 
                           ID=c(1,1,2,2,2,3,3,3,5,6,8,9,10,13,15,17,19,20,21,7))


  merge_data_2
   year amount ID
1  1999    100  1
2  1999    200  1
3  2000    300  2
4  2000    400  2
5  2000    500  2
6  2001    600  3
7  2003    700  3
8  2012    800  3
9  2009    900  5
10 2009   1000  6
11 2008   1100  8
12 2002   1200  9
13 2009   1300 10
14 2005   1400 13
15 2001   1500 15
16 2000   1600 17
17 2002   1700 19
18 2000   1800 20
19 2008   1900 21
20 2005   2000  7

我想要的是：

 ID position school year1 year2 amount
 1    yes    a      2000  1999  300
 2    no     b      2000  1999  1200
10    yes    e      2009  2008  1300

对于merge_data_2中的ID = 1，我们有金额= 300，因为有2个案例，其中ID = 1，并且他们的year1或year1等于merge_data中ID = 1的年份

所以基本上我想要的是根据ID和年份执行合并。 2条件：

merge_data中的ID与merge_data_2
merge_data的year1和year2之一也匹配merge_data_2中的年份。然后根据每个ID的金额总和进行合并。

我认为代码看起来像是：

merge_data_final <- merge(merge_data, merge_data_2, 
                          merge_data$ID == merge_data_2$ID && (merge_data$year1 || 
                            merge_data$year2 == merge_data_2$year))

Then somehow to aggregate the amount by ID.

显然我知道代码是错误的，而且我一直在考虑使用plyr或重塑库，但是很难掌握它们。

任何帮助都会很棒！谢谢你们！

Answer 1

如上所述，我认为您的示例输入和输出数据之间存在一些差异。这是基本方法 - 您使用reshape2走在正确的轨道上。您可以简单地melt()将数据library(reshape2) #melt into long format merge_data_m <- melt(merge_data, measure.vars = c("year1", "year2")) #merge together, specifying the joining columns merge(merge_data_m, merge_data_2, by.x = c("ID", "value"), by.y = c("ID", "year")) #----- ID value position school variable amount 1 1 1999 yes a year2 100 2 1 1999 yes a year2 200 3 2 2000 no b year1 500 4 2 2000 no b year1 300 5 2 2000 no b year1 400设置为长格式，这样您就可以加入一个列而不是之前的任何一个/或一个位。

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基于具有不同列名的2列合并2数据帧

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