from matrix to data.frame

?stack
x <- read.table(textConnection(" A  B  C  D  E
+ 1 1  6 11 16 21
+ 2 2  7 12 17 22
+ 3 3  8 13 18 23
+ 4 4  9 14 19 24
+ 5 5 10 15 20 25"), header=TRUE)
x
A  B  C  D  E
1 1  6 11 16 21
2 2  7 12 17 22
3 3  8 13 18 23
4 4  9 14 19 24
5 5 10 15 20 25
stack(x)
values ind
1       1   A
2       2   A
3       3   A
4       4   A
5       5   A
6       6   B
7       7   B
8       8   B
9       9   B
10     10   B
11     11   C
12     12   C
13     13   C
14     14   C
15     15   C
16     16   D
17     17   D
18     18   D
19     19   D
20     20   D
21     21   E
22     22   E
23     23   E
24     24   E
25     25   E

Hello,

I have a question how to reshape a given matrix to a data frame.

# ----------------------------------
a <- matrix(1:25, nrow=5)
a
    [,1] [,2] [,3] [,4] [,5]
[1,]    1    6   11   16   21
[2,]    2    7   12   17   22
[3,]    3    8   13   18   23
[4,]    4    9   14   19   24
[5,]    5   10   15   20   25

colnames(a) <- LETTERS[1:5]
rownames(a) <- as.character(1:5)
a
 A  B  C  D  E
1 1  6 11 16 21
2 2  7 12 17 22
3 3  8 13 18 23
4 4  9 14 19 24
5 5 10 15 20 25

# -----------------------------------

This is an example on how my matrix looks like.
Now, I'd like to reshape the data that I get a data frame with three
columns:

- the row name of the enty (X1)
- the column name of the entry (X2)
- the entry itself (X3)

like:

X1      X2      X3
1       A       1
2       A       2
3       A       3
....
1       B       6
2       B       7
....
5       E       25

How would you solve this problem in an elegant way?

Antje

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

from matrix to data.frame

Thread (6 messages)