如何组合R中相同数据帧的不同字符列

Question

我在R中有一个数据框如下:

D = data.frame(countrycode = c(2, 2, 2, 3, 3, 3), 
           year = c(1980, 1991, 2013, 1980, 1991, 2013), 
           hello = c("A", "B", "C", "D", "E", "F"), 
           world = c("Z", "Y", "X", "NA", "Q", "NA"), 
           foo = c("Yes", "No", "NA", "NA", "Yes", "NA"))

我想要列hello,world并foo合并在一个列中,索引为countrycode和year,如下所示:

output<-data.frame(countrycode=c(2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3),
    year=c(1980,1980,1980,1991,1991,1991,2013,2013,2013,1980,1980,1980,1991,1991,1991,2013,2013,2013),
    Combined=c("A","Z","Yes","B","Y","No","C","X","NA","D","NA","NA","E","Q","Yes","F","NA","NA"))

我都一直cbind从标准R和gather从tidyr包装,既不似乎工作.

Answer 1

我想你正在寻找包reshape2.请尝试以下代码:

library(reshape2)

output<-melt(D,id.vars=c("countrycode","year"))
output<-output[order(output$countrycode,output$year),]

它再现了你的例子.两个函数非常有用:融合和对立:dcast.