通过rownames合并R中的超过2个数据帧 [英] Merging more than 2 dataframes in R by rownames

问题描述

我收集4 df的数据，并希望以rownames合并它们。我正在寻找一种有效的方式来做到这一点。这是我拥有的数据的简化版本。

I gather data from 4 df's and would like to merge them by rownames. I am looking for an efficient way to do this. This is a simplified version of the data I have.

df1           <- data.frame(N= sample(seq(9, 27, 0.5), 40, replace= T),
                            P= sample(seq(0.3, 4, 0.1), 40, replace= T),
                            C= sample(seq(400, 500, 1), 40, replace= T))
df2           <- data.frame(origin= sample(c("A", "B", "C", "D", "E"), 40,
                                           replace= T),
                            foo1= sample(c(T, F), 40, replace= T),
                            X= sample(seq(145600, 148300, 100), 40, replace= T),
                            Y= sample(seq(349800, 398600, 100), 40, replace= T))
df3           <- matrix(sample(seq(0, 1, 0.01), 40), 40, 100)
df4           <- matrix(sample(seq(0, 1, 0.01), 40), 40, 100)
rownames(df1) <- paste("P", sprintf("%02d", c(1:40)), sep= "")
rownames(df2) <- rownames(df1)
rownames(df3) <- rownames(df1)
rownames(df4) <- rownames(df1)

这是我通常会做的：

# merge df1 and df2
dat           <- merge(df1, df2, by= "row.names", all.x= F, all.y= F) #merge
rownames(dat) <- dat$Row.names #reset rownames
dat$Row.names <- NULL  #remove added rownames col

# merge dat and df3
dat           <- merge(dat, df3, by= "row.names", all.x= F, all.y= F) #merge
rownames(dat) <- dat$Row.names #reset rownames
dat$Row.names <- NULL  #remove added rownames col

# merge dat and df4
dat           <- merge(dat, df4, by= "row.names", all.x= F, all.y= F) #merge
rownames(dat) <- dat$Row.names #reset rownames
dat$Row.names <- NULL #remove added rownames col

如您所见，这需要很多代码。我的问题是如果用更简单的手段实现相同的结果。我已经尝试了（没有成功）：更新：这个工作现在！

As you can see, this requires a lot of code. My question is if the same result can be achieved with more simple means. I've tried (without success): UPDATE: this works now!

MyMerge       <- function(x, y){
  df            <- merge(x, y, by= "row.names", all.x= F, all.y= F)
  rownames(df)  <- df$Row.names
  df$Row.names  <- NULL
  return(df)
}
dat           <- Reduce(MyMerge, list(df1, df2, df3, df4))

提前感谢任何建议

推荐答案

join_all 从 plyr 可能会做你想要的。但是它们都必须是数据框，并且rownames被添加为列

join_all from plyr will probably do what you want. But they all must be data frames and the rownames are added as a column

require(plyr)

df3 <- data.frame(df3)
df4 <- data.frame(df4)

df1$rn <- rownames(df1)
df2$rn <- rownames(df2)
df3$rn <- rownames(df3)
df4$rn <- rownames(df4)

df <- join_all(list(df1,df2,df3,df4), by = 'rn', type = 'full')

类型参数应该有帮助，即使rownames变化，不匹配
如果你不想要rownames：

type argument should help even if the rownames vary and do not match If you do not want the rownames:

df$rn <- NULL

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