Hoping there's a simple answer here but I can't find it anywhere.
I have a numeric matrix with labelled rows and columns:
1 2 3 4
a 6 7 8 9
b 8 7 5 7
c 8 5 4 1
d 1 6 3 2
I would like a data.table (or a data.frame I can then convert) of the form:
col row value
1 a 6
1 b 8
1 c 8
1 d 1
2 a 7
2 b 7
2 c 5
2 d 6
...
Any tips appreciated.
Use melt
from reshape2:
library(reshape2)
#Fake data
x <- matrix(1:12, ncol = 3)
colnames(x) <- letters[1:3]
rownames(x) <- 1:4
x.m <- melt(x)
x.m
Var1 Var2 value
1 1 a 1
2 2 a 2
3 3 a 3
4 4 a 4
...