Can I use RandomUnderSampler for categorical data as well?
Under/Over sampling has nothing to do with features. It relies on targets and under/oversamples majority/minority class, no matter whatheter it is composed of continuous variables, categorical ones, or elephants :)
AFAIK, unlike SMOTE,  RandomUnderSampler selects a subset of the data. But I am not quite confident to use it for categorical data.
So, is it really applicable for categorical data?