Merging more than 2 dataframes in R by rownames

Question

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) 

This is what I would normally do:

# 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 

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)) 

Thanks in advance for any suggestions

Answer 1

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') 

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

df$rn <- NULL