如何在不添加“Row.names"的情况下按行名称合并数据帧?柱子? [英] How does one merge dataframes by row name without adding a "Row.names" column?

问题描述

如果我有两个数据框，比如:

If I have two data frames, such as:

df1 = data.frame(x=1:3,y=1:3,row.names=c('r1','r2','r3'))
df2 = data.frame(z=5:7,row.names=c('r5','r6','r7'))

(

R> df1
   x y
r1 1 1
r2 2 2
r3 3 3

R> df2
   z
r5 5
r6 6
r7 7

)，我想按行名合并它们，保留所有内容(所以是外连接，或 all=T).这样做:

), I'd like to merge them by row names, keeping everything (so an outer join, or all=T). This does it:

merged.df <- merge(df1,df2,all=T,by='row.names')
R> merged.df
  Row.names  x  y  z
1        r1  1  1 NA
2        r2  2  2 NA
3        r3  3  3 NA
4        r5 NA NA  5
5        r6 NA NA  6
6        r7 NA NA  7

但我希望输入行名称是输出数据帧(merged.df)中的行名称.

but I want the input row names to be the row names in the output dataframe (merged.df).

我能做到:

rownames(merged.df) <- merged.df[[1]]
merged.df <- merged.df[-1]

哪个有效，但似乎不雅且难以记住.有人知道更清洁的方法吗?

which works, but seems inelegant and hard to remember. Anyone know of a cleaner way?

推荐答案

不确定是否更容易记住，但您可以使用 transform 一步完成所有操作.

Not sure if it's any easier to remember, but you can do it all in one step using transform.

transform(merge(df1,df2,by=0,all=TRUE), row.names=Row.names, Row.names=NULL)
#    x  y  z
#r1  1  1 NA
#r2  2  2 NA
#r3  3  3 NA
#r5 NA NA  5
#r6 NA NA  6
#r7 NA NA  7

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