Combine a list of data frames into one preserving row names
I do know about the basics of combining a list of data frames into one as has been answered before. However, I am interested in smart ways to maintain row names. Suppose I have a list of data frames that are fairly equal and I keep them in a named list.
library(plyr)
library(dplyr)
library(data.table)
a = data.frame(x=1:3, row.names = letters[1:3])
b = data.frame(x=4:6, row.names = letters[4:6])
c = data.frame(x=7:9, row.names = letters[7:9])
l = list(A=a, B=b, C=c)
When I use do.call, the list names are combined with the row names:
> rownames(do.call("rbind", l))
[1] "A.a" "A.b" "A.c" "B.d" "B.e" "B.f" "C.g" "C.h" "C.i"
When I use any of rbind.fill, bind_rows or rbindlist the row names are replaced by a numeric range:
> rownames(rbind.fill(l))
> rownames(bind_rows(l))
> rownames(rbindlist(l))
[1] "1" "2" "3" "4" "5" "6" "7" "8" "9"
When I remove the names from the list, do.call produces the desired output:
> names(l) = NULL
> rownames(do.call("rbind", l))
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i"
So is there a function that I'm missing that provides some finer control over the row names? I do need the names for a different context so removing them is sub-optimal.
Answer
To preserve rownames, you can simply do:
do.call(rbind, unname(l))
# x
#a 1
#b 2
#c 3
#d 4
#e 5
#f 6
#g 7
#h 8
#i 9
Or as you underlined by setting the rownames of l to NULL , this can be also done by:
do.call(rbind, setNames(l, NULL))