[R] display only the top-right half of a correlation matrix?

[Peter Langfelder]

On Fri, Aug 19, 2011 at 11:50 AM, Liviu Andronic <landronimirc at gmail.com> wrote:
> Dear all
> Is there an easy way to display only one half (top-right or
> bottom-left) of a correlation matrix?
>
>> require(Hmisc)
>> rcorr(as.matrix(mtcars[ , 1:4]))
>       mpg   cyl  disp    hp
> mpg   1.00 -0.85 -0.85 -0.78
> cyl  -0.85  1.00  0.90  0.83
> disp -0.85  0.90  1.00  0.79
> hp   -0.78  0.83  0.79  1.00
>

Use as.dist: here's an example.

> x = matrix(rnorm(5*100), 100, 5)
> as.dist(cor(x))
              1             2             3             4
2 -2.892981e-06
3  2.873711e-02  1.002969e-02
4 -5.803705e-02  4.022733e-02 -6.154211e-02
5  1.137083e-01 -8.065676e-02 -9.279316e-02 -8.201583e-02