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]