Getting loadings of components from pcaMethods

Question

[johnnytam100]

I want to get the loadings of components from pcaMethods.

To illustrate the problem, I have a matrix x

    a   b   c
1   ... ... ...
2   ... ... ...
3   ... ... ...

By loadings(pca(x, method="nipals", nPcs=2)), I get

    PC1 PC2
a   ... ...
b   ... ...
c   ... ...

However, I want to get

    PC1 PC2
1   ... ...
2   ... ...
3   ... ...

Anyone knows how to do that?

Thanks a lot!

Answer 1

[Philipp Bayer]

Wouldn't you just need to transpose your input table while keeping names intact?

tx = setNames(data.frame(t(x[,-1])), x[,1])
loadings(pca(tx, method="nipals", nPcs=2))

[johnnytam100]

Good idea! I had a similar thought but does it work for a PCA analysis that we just swap the columns and rows?