R对n列中的每n行求和

Question

我有一个看起来像这样的data.frame:

Geotype <- c(1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3)
Strategy <- c("Demand", "Strategy 1", "Strategy 2", "Strategy 3", "Strategy 4", "Strategy 5", "Strategy 6")
Year.1  <- c(1:21)
Year.2  <- c(1:21)
Year.3  <- c(1:21)
Year.4  <- c(1:21)
mydata <- data.frame(Geotype,Strategy,Year.1, Year.2, Year.3, Year.4) 

我想总结每一年的每项战略.

这意味着我需要在数据框中的每一列下面加6行,然后跳过Demand行.然后我想对所有专栏(40年)重复这一点.

我希望输出数据框看起来像这样:

Geotype.output <- c(1, 2, 3)
Year.1.output  <- c(27, 69, 111)
Year.2.output  <- c(27, 69, 111)
Year.3.output  <- c(27, 69, 111)
Year.4.output  <- c(27, 69, 111)
output <- data.frame(Geotype.output,Year.1.output, Year.2.output, Year.3.output, Year.4.output) 

关于如何优雅地做这个的任何建议？我试图用这个,这个和这个一起破解一个解决方案,但我没有成功,因为我需要跳过一行.

Answer 1

您可以尝试使用base R aggregate函数(通过Geotype使用函数sum作为"唯一值" 聚合数据)但使用简化的data.frame(不使用"Demand"行和Strategy列):

aggregate(.~Geotype, data=mydata[mydata$Strategy !="Demand", -2], FUN=sum)
#  Geotype Year.1 Year.2 Year.3 Year.4
#1       1     27     27     27     27
#2       2     69     69     69     69
#3       3    111    111    111    111

Answer 2

使用data.table:

library(data.table)
setDT(mydata)
output = mydata[Strategy != "Demand", 
             .(Year.1.output = sum (Year.1), 
               Year.2.output = sum (Year.2), 
               Year.3.output = sum (Year.3), 
               Year.4.output = sum (Year.4)),
             by = Geotype]

#    Geotype Year.1.output Year.2.output Year.3.output Year.4.output
# 1:       1            27            27            27            27
# 2:       2            69            69            69            69
# 3:       3           111           111           111           111

我们可以简化这个以便更容易地处理多年的专栏

setDT(mydata)[Strategy != "Demand", 
             lapply(.SD, sum), 
             by=Geotype, 
             .SDcols=grep("Year", names(mydata))]