diag
Syntax
diag(X)
Arguments
X is a numeric vector or a square matrix.
Details
If X is a vector: return a diagonal matrix.
If X is a square matrix: return a vector with the diagonal elements of the matrix.
Examples
$ diag(1..5);
#0 |
#1 |
#2 |
#3 |
#4 |
---|---|---|---|---|
1 |
0 |
0 |
0 |
0 |
0 |
2 |
0 |
0 |
0 |
0 |
0 |
3 |
0 |
0 |
0 |
0 |
0 |
4 |
0 |
0 |
0 |
0 |
0 |
5 |
$ m=1..4$2:2;
$ m;
#0 |
#1 |
---|---|
1 |
3 |
2 |
4 |
$ diag(m);
[1,4]