How can I rbind vectors matching their column names?

Question

rbind does not check for column names when binding together vectors:

l = list(row1 = c(10, 20), row2 = c(20, 10))
names(l$row1) = c(\"A\", \"B\")
names(l$row         


        

Answer 1

You can use match:

l <- list(row1 = setNames(1:3, c("A", "B", "C")),
          row2 = setNames(1:3, c("B", "C", "A")),
          row3 = setNames(1:3, c("C", "A", "B")))

do.call(rbind, lapply(l, function(x) x[match(names(l[[1]]), names(x))]))

The result:

     A B C
row1 1 2 3
row2 3 1 2
row3 2 3 1