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.
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