删除R中的重复项和求和值 [英] Remove duplicates and sum values in R

问题描述

我有一个数据集df，看起来像这样，但有几百万个实例：

I have a dataset, df, that looks like this but has a few million instances:


日期AD跑道MTOW航班
2008-01-01 A 18376 2
2008-01-01 A 18376 2
2008-01-01 D 36190 1
2008-01- 02 D 09 150 2
2008-01-02 A 36280 1
2008-01-02 A 36280 1


我希望它看起来像这样：

And I want it to look like this:


日期AD跑道MTOW nr.flights
2008-01-01 A 18752 4
2008-01-01 D 36190 2
2008-01-02 D 9150 2
2008-01-02 A 36560 1


基本上我想将所有相同的日期，AD和跑道行组合在一起，所以所有重复项都是删除。同时，我希望针对特定的日期，广告和跑道汇总MTOW和nr.flights。

Basically I want to group together all the Date, AD and Runway rows that are the same, so all the duplicates are removed. At the same time, I want the MTOW and nr.flights to be summed up for that particular Date, AD and Runway.

我已经尝试过：
vals<-expand.grid（Date = unique（df $ Date），
跑道=唯一（df $ Runway），
AD =唯一（df $ AD））

所以我可以合并这与原始数据集df一起使用，但无效。我还尝试了group_by的几种组合，但这也没有给我想要的结果。

So I could merge this with the original dataset, df, but that didn't work. I have also tried a few combinations of group_by but that also didn't give me the result that I wanted.

要重现：

df <- data.frame(Date=c("2008-01-01","2008-01-01","2008-01-01","2008-01-02","2008-01-02","2008-01-02"),
              AD = c("A", "A", "D", "D", "A", "A"), Runway = c(18, 18, 36, 09, 36,36), 
              MTOW = c(376, 376, 190, 150, 280, 280), nr.flights = c(2,2,1,2,1,1))

任何帮助将不胜感激！

Any help would be much appreciated!

推荐答案

这里是使用包 plyr 的一种：

library(plyr)
ddply(df,~Date + AD + Runway,summarise,MTOW=sum(MTOW),nr.flights=sum(nr.flights))

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