I've got two matrices which I want to interweave/interlace/stack alternatively on top of each other/rbind in an alternating manner.
ranks=1:3
names=c("Karl", "Klaus", "Mary")
x <- cbind(ranks, names)
universities=c("Cape Town", "London", "Berlin")
y <- cbind(rep("", 3), universities)
After one row of x, I want one row of y:
[,1] [,2]
[1,] "1" "Karl"
[2,] "" "Cape Town"
[3,] "2" "Klaus"
[4,] "" "London"
[5,] "3" "Mary"
[6,] "" "Berlin"
I tried matrix(rbind(x, y), ncol=2) (which seems to solve the problem if I had two strings) without effect
Here are two alternatives.
First, assuming we have to start with "x" and "y", you can try interleave from the "gdata" package:
library(gdata)
interleave(x, y)
# ranks names
# [1,] "1" "Karl"
# [2,] "" "Cape Town"
# [3,] "2" "Klaus"
# [4,] "" "London"
# [5,] "3" "Mary"
# [6,] "" "Berlin"
Second, assuming we can start with "ranks", "names", and "universities", you can use base R, like this:
cbind(c(t(cbind(ranks, ""))), c(t(cbind(names, universities))))
# [,1] [,2]
# [1,] "1" "Karl"
# [2,] "" "Cape Town"
# [3,] "2" "Klaus"
# [4,] "" "London"
# [5,] "3" "Mary"
# [6,] "" "Berlin"
A better alternative, however, would be to use something like melt (from "reshape2" or "data.table"). This would allow you to add another variable that indicates what type of measurement a value represents.
library(data.table)
melt(data.table(ranks, names, universities), "ranks")
# ranks variable value
# 1: 1 names Karl
# 2: 2 names Klaus
# 3: 3 names Mary
# 4: 1 universities Cape Town
# 5: 2 universities London
# 6: 3 universities Berlin
Or, to match your desired ordering:
library(data.table)
setorder(melt(data.table(ranks, names, universities), "ranks"), ranks)[]
# ranks variable value
# 1: 1 names Karl
# 2: 1 universities Cape Town
# 3: 2 names Klaus
# 4: 2 universities London
# 5: 3 names Mary
# 6: 3 universities Berlin