如何在R中合并和添加列？

I have two dataframes.

我有两个数据帧。

Seasons Frequency
DJF 1
JJA 10
MAM 20
SON 30

And

和

Seasons Frequency
DJF 1
JJA 10
MAM 20
SON 30

How can I merge these two dfs, at the same time adding the Frequency values?

如何合并这两个dfs，同时添加频率值？

Intended output:

预期产量：

Seasons Frequency
DJF 2
JJA 20
MAM 40
SON 60

3 个解决方案

#1

Using package plyr

使用包plyr

require(plyr)
ddply(rbind(df1, df2), 
  .(Seasons), 
  summarize,
  Frequency=sum(Frequency))

#2

If they're in order, with no missing labels, you can just add the second column.

如果它们是有序的，没有丢失标签，您只需添加第二列。

df1$Frequency <- df1$Frequency + df2$Frequency)

If not, you can merge on the Seasons values, then add the two together and drop the extraneous column.

如果没有，您可以合并Seasons值，然后将两者一起添加并删除无关列。

final.df <- merge(df1, df2, by='Seasons')
final.df$Frequency <- final.df$Frequency.x + final.df$Frequency.y
final.df$Frequency.x <- NULL
final.df$Frequency.y <- NULL

#3

Since 2 dataframes have identical structure, a one line code of base R will also do:

由于2个数据帧具有相同的结构，因此基数R的单行代码也将执行：

> df3 = data.frame(Seasons = df1$Seasons, Frequency = df1$Frequency+df2$Frequency)
> df3
  Seasons Frequency
1     DJF         2
2     JJA        20
3     MAM        40
4     SON        60

#1