NateGarrettHC

Make it so the print method returns the ignored columns specified in prep_data.

Whenever a column has only one value, when it gets centered and scaled, the step converts that column to all NAs. And if NAs are fed into the PCA step,...

Create a function/plot for variable loadings for PCA. Plot option to consider:  http://www.sthda.com/english/articles/31-principal-component-methods-in-r-practical-guide/112-pca-principal-component-analysis-essentials/