I used the factoextra package to make the biplot with top=20 contributed vars. The code is:
fviz_pca_biplot(pca_result1, title = "", col.var = "steelblue", select.var = list(contrib = 20))
The result is very nice for me. However, I have a problem that I need the name of those 20 vars in a list format that I can use later. Do you know any way to do that, except writing down the name of top=20 vars from the biplot graph?