[R] extract prop. of. var in pca

K. Steinmann Katharina.Steinmann at stud.unibas.ch
Fri Jul 8 20:51:12 CEST 2005

Dear R-helpers,

Using the package Lattice, I performed a PCA.

For example
pca.summary <- summary(pc.cr <- princomp(USArrests, cor = TRUE))

The Output of "pca.summary" looks as follows:

Importance of components:
                          Comp.1    Comp.2    Comp.3     Comp.4
Standard deviation     1.5748783 0.9948694 0.5971291 0.41644938
Proportion of Variance 0.6200604 0.2474413 0.0891408 0.04335752
Cumulative Proportion  0.6200604 0.8675017 0.9566425 1.00000000

How can I extract the proportion of variance?

Since names(pca.summary) or str(pca.summary) do not contain the proportion of
it seems I can not use something similar like pca.summary[[2]]$Comp.1[3].
I can't see how the values are stored.

Thanks in advance.

K. St.

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