[R] Reshape matrix from wide to long format
Daren Tan
daren76 at hotmail.com
Tue Nov 25 13:19:26 CET 2008
I forgot the reshape equivalent for converting from wide to long format. Can someone help as my matrix is very big. The followin is just an example.
> m <- matrix(1:20, nrow=4, dimnames=list(LETTERS[1:4], letters[1:5]))
> m
a b c d e
A 1 5 9 13 17
B 2 6 10 14 18
C 3 7 11 15 19
D 4 8 12 16 20
> as.data.frame(cbind(rep(rownames(m), ncol(m)), rep(colnames(m), each=nrow(m)), c(m)))
V1 V2 V3
1 A a 1
2 B a 2
3 C a 3
4 D a 4
5 A b 5
6 B b 6
7 C b 7
8 D b 8
9 A c 9
10 B c 10
11 C c 11
12 D c 12
13 A d 13
14 B d 14
15 C d 15
16 D d 16
17 A e 17
18 B e 18
19 C e 19
20 D e 20
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