r Change line width of eigenvectors in autoplot pca

Question

In R, one can easily display eigenvectors in PCA ordination plots using the autoplot function from the ggfortify package, as per the sample code below:

library(ggfortify)
library(ggrepel)

data(iris)
df <- iris[1:4]

pca_res <- prcomp(df, scale. = TRUE)

plt <- plot(autoplot(
  pca_res,
  data = iris,
  colour = 'Species',
  label.size = 3,
  loadings = TRUE,
  loadings.colour = "red",
  loadings.label = TRUE,
  loadings.label.repel = TRUE,
  loadings.label.size = 3
))

plt

With such code, it is possible to control the colours of eigenvectors, however I could not find any way of changing the line width of the eigenvectors.

Could someone tell how to do that?

Answer 1

I don't think you can do this directly within the function call, but you can do it indirectly after the object is created.

Your code creates the following plot:

plt

But if we do

plt$layers[[2]]$aes_params$size <- 3

Then we change it to

plt

^{Created on 2022-10-14 with reprex v2.0.2}